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Cvrčková F, Ghosh R, Kočová H. Transmembrane formins as active cargoes of membrane trafficking. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3668-3684. [PMID: 38401146 PMCID: PMC11194305 DOI: 10.1093/jxb/erae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 02/23/2024] [Indexed: 02/26/2024]
Abstract
Formins are a large, evolutionarily old family of cytoskeletal regulators whose roles include actin capping and nucleation, as well as modulation of microtubule dynamics. The plant class I formin clade is characterized by a unique domain organization, as most of its members are transmembrane proteins with possible cell wall-binding motifs exposed to the extracytoplasmic space-a structure that appears to be a synapomorphy of the plant kingdom. While such transmembrane formins are traditionally considered mainly as plasmalemma-localized proteins contributing to the organization of the cell cortex, we review, from a cell biology perspective, the growing evidence that they can also, at least temporarily, reside (and in some cases also function) in endomembranes including secretory and endocytotic pathway compartments, the endoplasmic reticulum, the nuclear envelope, and the tonoplast. Based on this evidence, we propose that class I formins may thus serve as 'active cargoes' of membrane trafficking-membrane-embedded proteins that modulate the fate of endo- or exocytotic compartments while being transported by them.
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Affiliation(s)
- Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Rajdeep Ghosh
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Helena Kočová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
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2
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Xu L, Cao L, Li J, Staiger CJ. Cooperative actin filament nucleation by the Arp2/3 complex and formins maintains the homeostatic cortical array in Arabidopsis epidermal cells. THE PLANT CELL 2024; 36:764-789. [PMID: 38057163 PMCID: PMC10896301 DOI: 10.1093/plcell/koad301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 12/08/2023]
Abstract
Precise control over how and where actin filaments are created leads to the construction of unique cytoskeletal arrays within a common cytoplasm. Actin filament nucleators are key players in this activity and include the conserved actin-related protein 2/3 (Arp2/3) complex as well as a large family of formins. In some eukaryotic cells, these nucleators compete for a common pool of actin monomers and loss of one favors the activity of the other. To test whether this mechanism is conserved, we combined the ability to image single filament dynamics in the homeostatic cortical actin array of living Arabidopsis (Arabidopsis thaliana) epidermal cells with genetic and/or small molecule inhibitor approaches to stably or acutely disrupt nucleator activity. We found that Arp2/3 mutants or acute CK-666 treatment markedly reduced the frequency of side-branched nucleation events as well as overall actin filament abundance. We also confirmed that plant formins contribute to side-branched filament nucleation in vivo. Surprisingly, simultaneous inhibition of both classes of nucleator increased overall actin filament abundance and enhanced the frequency of de novo nucleation events by an unknown mechanism. Collectively, our findings suggest that multiple actin nucleation mechanisms cooperate to generate and maintain the homeostatic cortical array of plant epidermal cells.
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Affiliation(s)
- Liyuan Xu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Lingyan Cao
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jiejie Li
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Christopher J Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- EMBRIO Institute, Purdue University, West Lafayette, IN 47907, USA
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3
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Zhang Z, Zhang Z, Shan M, Amjad Z, Xue J, Zhang Z, Wang J, Guo Y. Genome-Wide Studies of FH Family Members in Soybean ( Glycine max) and Their Responses under Abiotic Stresses. PLANTS (BASEL, SWITZERLAND) 2024; 13:276. [PMID: 38256829 PMCID: PMC10820127 DOI: 10.3390/plants13020276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024]
Abstract
Formins or formin homology 2 (FH2) proteins, evolutionarily conserved multi-domain proteins in eukaryotes, serve as pivotal actin organizers, orchestrating the structure and dynamics of the actin cytoskeleton. However, a comprehensive investigation into the formin family and their plausible involvement in abiotic stress remains undocumented in soybean (Glycine max). In the current study, 34 soybean FH (GmFH)family members were discerned, their genomic distribution spanning the twenty chromosomes in a non-uniform pattern. Evolutionary analysis of the FH gene family across plant species delineated five discernible groups (Group I to V) and displayed a closer evolutionary relationship within Glycine soja, Glycine max, and Arabidopsis thaliana. Analysis of the gene structure of GmFH unveiled variable sequence lengths and substantial diversity in conserved motifs. Structural prediction in the promoter regions of GmFH gene suggested a large set of cis-acting elements associated with hormone signaling, plant growth and development, and stress responses. The investigation of the syntenic relationship revealed a greater convergence of GmFH genes with dicots, indicating a close evolutionary affinity. Transcriptome data unveiled distinctive expression patterns of several GmFH genes across diverse plant tissues and developmental stages, underscoring a spatiotemporal regulatory framework governing the transcriptional dynamics of GmFH gene. Gene expression and qRT-PCR analysis identified many GmFH genes with a dynamic pattern in response to abiotic stresses, revealing their potential roles in regulating plant stress adaptation. Additionally, protein interaction analysis highlighted an intricate web of interactions among diverse GmFH proteins. These findings collectively underscore a novel biological function of GmFH proteins in facilitating stress adaptation in soybeans.
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Affiliation(s)
- Zhenbiao Zhang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zhongqi Zhang
- Heze Academy of Agricultural Sciences, Heze 274000, China
| | - Muhammad Shan
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zarmeena Amjad
- SINO_PAK Joint Research Laboratory, Institute of Plant Breeding and Biotechnology, MNS University of Agriculture, Multan 60000, Pakistan
| | - Jin Xue
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zenglin Zhang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Jie Wang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Yongfeng Guo
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
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4
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Cheng SY, Chu PK, Chen YJ, Wu YH, Huang MD. Exploring the extensin gene family: an updated genome-wide survey in plants and algae. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:152-167. [PMID: 37769205 DOI: 10.1093/jxb/erad380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/27/2023] [Indexed: 09/30/2023]
Abstract
Extensins (EXTs), a class of hydroxyproline-rich glycoprotein with multiple Ser-Pro3-5 motifs, are known to play roles in cell wall reinforcement and environmental responses. EXTs with repetitive Tyr-X-Tyr (YXY) motifs for crosslinking are referred as crosslinking EXTs. Our comprehensive study spanned 194 algal and plant species, categorizing EXTs into seven subfamilies: classical extensins (EXT I and II), arabinogalactan-protein extensins (AGP-EXTs), proline-rich extensin-like receptor kinases (PERKs), leucine-rich repeat extensins (LRX I and II), formin homology (FH) domain-containing extensins (FH-EXTs), proline-rich, arabinogalactan proteins, conserved cysteines (PAC) domain-containing extensins (PAC I and II), and eight-cysteine motif (8CM)-containing extensins (8CM-EXTs). In the examined dataset, EXTs were detected ubiquitously in plants but infrequently in algae, except for one Coccomyxa and four Chlamydomonadales species. No crosslinking EXTs were found in Poales or certain Zingiberales species. Notably, the previously uncharacterized EXT II, PAC II, and liverwort-specific 8CM-EXTs were found to be crosslinking EXTs. EXT II, featuring repetitive YY motifs instead of the conventional YXY motif, was exclusively identified in Solanaceae. Furthermore, tandem genes encoding distinctive 8CM-EXTs specifically expressed in the germinating spores of Marchantia polymorpha. This updated classification of EXT types allows us to propose a plausible evolutionary history of EXT genes during the course of plant evolution.
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Affiliation(s)
- Sou-Yu Cheng
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ping-Kuan Chu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Yi-Jing Chen
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Yun-Hsuan Wu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ming-Der Huang
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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5
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Hembrow J, Deeks MJ, Richards DM. Automatic extraction of actin networks in plants. PLoS Comput Biol 2023; 19:e1011407. [PMID: 37647341 PMCID: PMC10497154 DOI: 10.1371/journal.pcbi.1011407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 09/12/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023] Open
Abstract
The actin cytoskeleton is essential in eukaryotes, not least in the plant kingdom where it plays key roles in cell expansion, cell division, environmental responses and pathogen defence. Yet, the precise structure-function relationships of properties of the actin network in plants are still to be unravelled, including details of how the network configuration depends upon cell type, tissue type and developmental stage. Part of the problem lies in the difficulty of extracting high-quality, quantitative measures of actin network features from microscopy data. To address this problem, we have developed DRAGoN, a novel image analysis algorithm that can automatically extract the actin network across a range of cell types, providing seventeen different quantitative measures that describe the network at a local level. Using this algorithm, we then studied a number of cases in Arabidopsis thaliana, including several different tissues, a variety of actin-affected mutants, and cells responding to powdery mildew. In many cases we found statistically-significant differences in actin network properties. In addition to these results, our algorithm is designed to be easily adaptable to other tissues, mutants and plants, and so will be a valuable asset for the study and future biological engineering of the actin cytoskeleton in globally-important crops.
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Affiliation(s)
- Jordan Hembrow
- Living Systems Institute and Department of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Michael J. Deeks
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - David M. Richards
- Living Systems Institute and Department of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
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6
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The Cytoskeleton in Plant Immunity: Dynamics, Regulation, and Function. Int J Mol Sci 2022; 23:ijms232415553. [PMID: 36555194 PMCID: PMC9779068 DOI: 10.3390/ijms232415553] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/04/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
The plant cytoskeleton, consisting of actin filaments and microtubules, is a highly dynamic filamentous framework involved in plant growth, development, and stress responses. Recently, research has demonstrated that the plant cytoskeleton undergoes rapid remodeling upon sensing pathogen attacks, coordinating the formation of microdomain immune complexes, the dynamic and turnover of pattern-recognizing receptors (PRRs), the movement and aggregation of organelles, and the transportation of defense compounds, thus serving as an important platform for responding to pathogen infections. Meanwhile, pathogens produce effectors targeting the cytoskeleton to achieve pathogenicity. Recent findings have uncovered several cytoskeleton-associated proteins mediating cytoskeletal remodeling and defense signaling. Furthermore, the reorganization of the actin cytoskeleton is revealed to further feedback-regulate reactive oxygen species (ROS) production and trigger salicylic acid (SA) signaling, suggesting an extremely complex role of the cytoskeleton in plant immunity. Here, we describe recent advances in understanding the host cytoskeleton dynamics upon sensing pathogens and summarize the effectors that target the cytoskeleton. We highlight advances in the regulation of cytoskeletal remodeling associated with the defense response and assess the important function of the rearrangement of the cytoskeleton in the immune response. Finally, we propose suggestions for future research in this area.
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Dong M, Xue S, Bartholomew ES, Zhai X, Sun L, Xu S, Zhang Y, Yin S, Ma W, Chen S, Feng Z, Geng C, Li X, Liu X, Ren H. Transcriptomic and functional analysis provides molecular insights into multicellular trichome development. PLANT PHYSIOLOGY 2022; 189:301-314. [PMID: 35171294 PMCID: PMC9070826 DOI: 10.1093/plphys/kiac050] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 01/13/2022] [Indexed: 05/31/2023]
Abstract
Trichomes, the hair-like structures located on aerial parts of most vascular plants, are associated with a wide array of biological processes and affect the economic value of certain species. The processes involved in unicellular trichome formation have been well-studied in Arabidopsis (Arabidopsis thaliana). However, our understanding of the morphological changes and the underlying molecular processes involved in multicellular trichome development is limited. Here, we studied the dynamic developmental processes involved in glandular and nonglandular multicellular trichome formation in cucumber (Cucumis sativus L.) and divided these processes into five sequential stages. To gain insights into the underlying mechanisms of multicellular trichome formation, we performed a time-course transcriptome analysis using RNA-sequencing analysis. A total of 711 multicellular trichome-related genes were screened and a model for multicellular trichome formation was developed. The transcriptome and co-expression datasets were validated by reverse transcription-quantitative PCR and in situ hybridization. In addition, virus-induced gene silencing analysis revealed that CsHOMEOBOX3 (CsHOX3) and CsbHLH1 are involved in nonglandular trichome elongation and glandular trichome formation, respectively, which corresponds with the transcriptome data. This study presents a transcriptome atlas that provides insights into the molecular processes involved in multicellular trichome formation in cucumber and can be an important resource for future functional studies.
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Affiliation(s)
- Mingming Dong
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Shudan Xue
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Ezra S Bartholomew
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Xuling Zhai
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Lei Sun
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Shuo Xu
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Yaqi Zhang
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Shuai Yin
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Wenyue Ma
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Shuying Chen
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Zhongxuan Feng
- Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Chao Geng
- Department of Plant Pathology, Shandong Provincial Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China
| | - Xiangdong Li
- Department of Plant Pathology, Shandong Provincial Key Laboratory of Agricultural Microbiology, College of Plant Protection, Shandong Agricultural University, Tai’an 271018, China
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8
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Ma Z, Sun Y, Zhu X, Yang L, Chen X, Miao Y. Membrane nanodomains modulate formin condensation for actin remodeling in Arabidopsis innate immune responses. THE PLANT CELL 2022; 34:374-394. [PMID: 34726756 PMCID: PMC8774048 DOI: 10.1093/plcell/koab261] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/20/2021] [Indexed: 05/23/2023]
Abstract
The assembly of macromolecules on the plasma membrane concentrates cell surface biomolecules into nanometer- to micrometer-scale clusters (nano- or microdomains) that help the cell initiate or respond to signals. In plant-microbe interactions, the actin cytoskeleton undergoes rapid remodeling during pathogen-associated molecular pattern-triggered immunity (PTI). The nanoclustering of formin-actin nucleator proteins at the cell surface has been identified as underlying actin nucleation during plant innate immune responses. Here, we show that the condensation of nanodomain constituents and the self-assembly of remorin proteins enables this mechanism of controlling formin condensation and activity during innate immunity in Arabidopsis thaliana. Through intrinsically disordered region-mediated remorin oligomerization and formin interaction, remorin gradually recruits and condenses formins upon PTI activation in lipid bilayers, consequently increasing actin nucleation in a time-dependent manner postinfection. Such nanodomain- and remorin-mediated regulation of plant surface biomolecules is expected to be a general feature of plant innate immune responses that creates spatially separated biochemical compartments and fine tunes membrane physicochemical properties for transduction of immune signals in the host.
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Affiliation(s)
- Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yanbiao Sun
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Centre, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xinlu Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, China
| | - Xu Chen
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Centre, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Qin L, Liu L, Tu J, Yang G, Wang S, Quilichini TD, Gao P, Wang H, Peng G, Blancaflor EB, Datla R, Xiang D, Wilson KE, Wei Y. The ARP2/3 complex, acting cooperatively with Class I formins, modulates penetration resistance in Arabidopsis against powdery mildew invasion. THE PLANT CELL 2021; 33:3151-3175. [PMID: 34181022 PMCID: PMC8462814 DOI: 10.1093/plcell/koab170] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/20/2021] [Indexed: 05/19/2023]
Abstract
The actin cytoskeleton regulates an array of diverse cellular activities that support the establishment of plant-microbe interactions and plays a critical role in the execution of plant immunity. However, molecular and cellular mechanisms regulating the assembly and rearrangement of actin filaments (AFs) at plant-pathogen interaction sites remain largely elusive. Here, using live-cell imaging, we show that one of the earliest cellular responses in Arabidopsis thaliana upon powdery mildew attack is the formation of patch-like AF structures beneath fungal invasion sites. The AFs constituting actin patches undergo rapid turnover, which is regulated by the actin-related protein (ARP)2/3 complex and its activator, the WAVE/SCAR regulatory complex (W/SRC). The focal accumulation of phosphatidylinositol-4,5-bisphosphate at fungal penetration sites appears to be a crucial upstream modulator of the W/SRC-ARP2/3 pathway-mediated actin patch formation. Knockout of W/SRC-ARP2/3 pathway subunits partially compromised penetration resistance with impaired endocytic recycling of the defense-associated t-SNARE protein PEN1 and its deposition into apoplastic papillae. Simultaneously knocking out ARP3 and knocking down the Class I formin (AtFH1) abolished actin patch formation, severely impaired the deposition of cell wall appositions, and promoted powdery mildew entry into host cells. Our results demonstrate that the ARP2/3 complex and formins, two actin-nucleating systems, act cooperatively and contribute to Arabidopsis penetration resistance to fungal invasion.
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Affiliation(s)
- Li Qin
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - Lijiang Liu
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, Hubei 430062, China
| | - Jiangying Tu
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, SK S7N 0X2, Canada
| | - Guogen Yang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Anhui Agricultural University, Hefei 230036, China
| | - Sheng Wang
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | | | - Peng Gao
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 0W9, Canada
| | - Hong Wang
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada
| | - Gary Peng
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, Saskatoon, SK S7N 0X2, Canada
| | | | - Raju Datla
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 0W9, Canada
| | - Daoquan Xiang
- National Research Council Canada, Saskatoon, SK, S7N 0W9, Canada
| | - Kenneth E. Wilson
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
| | - Yangdou Wei
- Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada
- Author for correspondence:
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10
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Formin-like protein 2 promotes cell proliferation by a p27-related mechanism in human breast cancer cells. BMC Cancer 2021; 21:760. [PMID: 34193109 PMCID: PMC8247103 DOI: 10.1186/s12885-021-08533-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 06/23/2021] [Indexed: 12/25/2022] Open
Abstract
Background Breast cancer is the leading cause of cancer-related deaths in females worldwide. Formin-like protein 2 (FMNL2) is a member of formin family that governs cytokinesis, cell polarity, morphogenesis and cell division. To our knowledge, the function of FMNL2 in breast cancer proliferation still remains uncovered. Methods Tumor immune estimation resource (TIMER) analysis was used to detect the correlation between FMNL2 and Ki67 in breast cancer tissues. Quantitative real-time transcription polymerase chain reaction (qRT-PCR) and western blotting were performed to analyze the expression in human breast cancer cells. Moreover, RNA interference (RNAi) and plasmids were performed to silence and overexpress FMNL2 and p27. The CCK8, MTT, cell counting, colony formation, and 5-ethynyl-2-deoxyuridine (EdU) incorporation assays were used to detect cell proliferation, respectively. Flow cytometry analysis was used to detect cell cycle distribution. Further, the distribution of p27 was examined using immunofluorescence. Results We found that FMNL2 expression was positively associated with Ki67 among collected breast cancer tissues and in TCGA database. Compared to lower proliferative cells MCF7 and T47D, FMNL2 was overexpressed in highly proliferative breast cancer cells MDA-MB-231, BT549 and SUM159, accompanied by reduced levels of p27 and p21, and elevated CyclinD1 and Ki67 expression. FMNL2 silencing significantly inhibited the cell proliferation of MDA-MB-231 and BT549 cells. Meanwhile, FMNL2 overexpression distinctly promoted the cell proliferation of MCF7 cells. Furthermore, FMNL2 suppressed the nuclear levels of p27 and promoted p27 proteasomal degradation in human breast cancer cells. The ubiquitination of p27 was inhibited by FMNL2 silencing in BT549 cells. Besides, p27 silencing markedly elevated Ki67 expression and cell viability, which could be blocked by additionally FMNL2 silencing in MDA-MB-231 and BT549 cells. Furthermore, overexpression of p27WT significantly reversed the increased levels of FMNL2 and Ki67, cell viability and cell cycle progression induced by FMNL2 overexpression in MCF7 cells. More importantly, compared to p27WT group, those effects could be significantly reversed by p27△NLS overexpression. Conclusions These results demonstrated that FMNL2 promoted cell proliferation partially by reducing p27 nuclear localization and p27 protein stability in human breast cancer cells, suggesting the pivotal role of FMNL2 in breast cancer progression. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-021-08533-w.
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Ramakrishna P. Formins bridle and unleash their way through cytokinesis: a phragmoplast-centered view. PLANT PHYSIOLOGY 2021; 186:829-831. [PMID: 33842968 PMCID: PMC8195534 DOI: 10.1093/plphys/kiab148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Priya Ramakrishna
- Department of Botany and Plant Biology, University of Geneva, Switzerland
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12
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Zhang L, Smertenko T, Fahy D, Koteyeva N, Moroz N, Kuchařová A, Novák D, Manoilov E, Smertenko P, Galva C, Šamaj J, Kostyukova AS, Sedbrook JC, Smertenko A. Analysis of formin functions during cytokinesis using specific inhibitor SMIFH2. PLANT PHYSIOLOGY 2021; 186:945-963. [PMID: 33620500 PMCID: PMC8195507 DOI: 10.1093/plphys/kiab085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/03/2021] [Indexed: 05/10/2023]
Abstract
The phragmoplast separates daughter cells during cytokinesis by constructing the cell plate, which depends on interaction between cytoskeleton and membrane compartments. Proteins responsible for these interactions remain unknown, but formins can link cytoskeleton with membranes and several members of formin protein family localize to the cell plate. Progress in functional characterization of formins in cytokinesis is hindered by functional redundancies within the large formin gene family. We addressed this limitation by employing Small Molecular Inhibitor of Formin Homology 2 (SMIFH2), a small-molecule inhibitor of formins. Treatment of tobacco (Nicotiana tabacum) tissue culture cells with SMIFH2 perturbed localization of actin at the cell plate; slowed down both microtubule polymerization and phragmoplast expansion; diminished association of dynamin-related proteins with the cell plate independently of actin and microtubules; and caused cell plate swelling. Another impact of SMIFH2 was shortening of the END BINDING1b (EB1b) and EB1c comets on the growing microtubule plus ends in N. tabacum tissue culture cells and Arabidopsis thaliana cotyledon epidermis cells. The shape of the EB1 comets in the SMIFH2-treated cells resembled that of the knockdown mutant of plant Xenopus Microtubule-Associated protein of 215 kDa (XMAP215) homolog MICROTUBULE ORGANIZATION 1/GEMINI 1 (MOR1/GEM1). This outcome suggests that formins promote elongation of tubulin flares on the growing plus ends. Formins AtFH1 (A. thaliana Formin Homology 1) and AtFH8 can also interact with EB1. Besides cytokinesis, formins function in the mitotic spindle assembly and metaphase to anaphase transition. Our data suggest that during cytokinesis formins function in: (1) promoting microtubule polymerization; (2) nucleating F-actin at the cell plate; (3) retaining dynamin-related proteins at the cell plate; and (4) remodeling of the cell plate membrane.
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Affiliation(s)
- Laining Zhang
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Tetyana Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Deirdre Fahy
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Nuria Koteyeva
- Laboratory of Anatomy and Morphology, Komarov Botanical Institute of Russian Academy of Sciences, St. Petersburg 197376, Russia
| | - Natalia Moroz
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, USA
| | - Anna Kuchařová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Dominik Novák
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Eduard Manoilov
- V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
| | - Petro Smertenko
- V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
| | - Charitha Galva
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Jozef Šamaj
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Alla S. Kostyukova
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, USA
| | - John C. Sedbrook
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
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13
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Plant biology: Plant formins roll out the welcome wagon for microbes. Curr Biol 2021; 31:R788-R791. [PMID: 34157262 DOI: 10.1016/j.cub.2021.04.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The interactions of microbes with plant cells can radically change plant-cell form and function. A new study shows how a specialised formin protein paves the way for nitrogen-fixing bacteria to make homes in legumes.
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14
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Ma Z, Liu X, Nath S, Sun H, Tran TM, Yang L, Mayor S, Miao Y. Formin nanoclustering-mediated actin assembly during plant flagellin and DSF signaling. Cell Rep 2021; 34:108884. [PMID: 33789103 DOI: 10.1016/j.celrep.2021.108884] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/11/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022] Open
Abstract
Plants respond to bacterial infection acutely with actin remodeling during plant immune responses. The mechanisms by which bacterial virulence factors (VFs) modulate plant actin polymerization remain enigmatic. Here, we show that plant-type-I formin serves as the molecular sensor for actin remodeling in response to two bacterial VFs: Xanthomonas campestris pv. campestris (Xcc) diffusible signal factor (DSF), and pathogen-associated molecular pattern (PAMP) flagellin in pattern-triggered immunity (PTI). Both VFs regulate actin assembly by tuning the clustering and nucleation activity of formin on the plasma membrane (PM) at the nano-sized scale. By being integrated within the cell-wall-PM-actin cytoskeleton (CW-PM-AC) continuum, the dynamic behavior and function of formins are highly dependent on each scaffold layer's composition within the CW-PM-AC continuum during both DSF and PTI signaling. Our results reveal a central mechanism for rapid actin remodeling during plant-bacteria interactions, in which bacterial signaling molecules fine tune plant formin nanoclustering in a host mechanical-structure-dependent manner.
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Affiliation(s)
- Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xiaolin Liu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bellary Road, Bangalore 560065, India; Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore 560065, India
| | - He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Blvd., Nanshan District, Shenzhen 518055, China
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bellary Road, Bangalore 560065, India; National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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15
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Kollárová E, Baquero Forero A, Cvrčková F. The Arabidopsis thaliana Class II Formin FH13 Modulates Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:599961. [PMID: 33679824 PMCID: PMC7929981 DOI: 10.3389/fpls.2021.599961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/29/2021] [Indexed: 05/10/2023]
Abstract
Formins are a large, evolutionarily conserved family of actin-nucleating proteins with additional roles in regulating microfilament, microtubule, and membrane dynamics. Angiosperm formins, expressed in both sporophytic and gametophytic tissues, can be divided into two subfamilies, Class I and Class II, each often exhibiting characteristic domain organization. Gametophytically expressed Class I formins have been documented to mediate plasma membrane-based actin assembly in pollen grains and pollen tubes, contributing to proper pollen germination and pollen tube tip growth, and a rice Class II formin, FH5/RMD, has been proposed to act as a positive regulator of pollen tube growth based on mutant phenotype and overexpression data. Here we report functional characterization of the Arabidopsis thaliana pollen-expressed typical Class II formin FH13 (At5g58160). Consistent with published transcriptome data, live-cell imaging in transgenic plants expressing fluorescent protein-tagged FH13 under the control of the FH13 promoter revealed expression in pollen and pollen tubes with non-homogeneous signal distribution in pollen tube cytoplasm, suggesting that this formin functions in the male gametophyte. Surprisingly, fh13 loss of function mutations do not affect plant fertility but result in stimulation of in vitro pollen tube growth, while tagged FH13 overexpression inhibits pollen tube elongation. Pollen tubes of mutants expressing a fluorescent actin marker exhibited possible minor alterations of actin organization. Our results thus indicate that FH13 controls or limits pollen tube growth, or, more generally, that typical Class II formins should be understood as modulators of pollen tube elongation rather than merely components of the molecular apparatus executing tip growth.
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16
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van Gisbergen P, Wu SZ, Cheng X, Pattavina KA, Bezanilla M. In vivo analysis of formin dynamics in the moss P. patens reveals functional class diversification. J Cell Sci 2020; 133:jcs233791. [PMID: 31969472 PMCID: PMC10679510 DOI: 10.1242/jcs.233791] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 01/07/2020] [Indexed: 01/02/2023] Open
Abstract
Formins are actin regulators critical for diverse processes across eukaryotes. With many formins in plants and animals, it has been challenging to determine formin function in vivo We found that the phylogenetically distinct class I integral membrane formins (denoted For1) from the moss P.patens enrich at sites of membrane turnover, with For1D more tightly associated with the plasma membrane than For1A. To probe formin function, we generated formin-null lines with greatly reduced formin complexity. We found that For1A and For1D help to anchor actin near the cell apex, with For1A contributing to formation of cytosolic actin, while For1D contributes to plasma membrane-associated actin. At the cortex, For1A and For1D localized to motile puncta and differentially impacted actin dynamics. We found that class I cortical formin mobility depended on microtubules and only moderately on actin, whereas class II formin (denoted For2) mobility solely depended on actin. Moreover, cortical For2A tightly correlated with the puncta labeled by the endocytic membrane dye FM4-64, and null mutants in class I formins did not affect uptake of a similar dye, FM1-43, suggesting that class I and II formins are involved in distinct membrane trafficking pathways.
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Affiliation(s)
- Peter van Gisbergen
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Kelli A Pattavina
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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17
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Kollárová E, Baquero Forero A, Stillerová L, Přerostová S, Cvrčková F. Arabidopsis Class II Formins AtFH13 and AtFH14 Can Form Heterodimers but Exhibit Distinct Patterns of Cellular Localization. Int J Mol Sci 2020; 21:E348. [PMID: 31948069 PMCID: PMC6982070 DOI: 10.3390/ijms21010348] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/30/2019] [Accepted: 01/03/2020] [Indexed: 12/25/2022] Open
Abstract
Formins are evolutionarily conserved multi-domain proteins participating in the control of both actin and microtubule dynamics. Angiosperm formins form two evolutionarily distinct families, Class I and Class II, with class-specific domain layouts. The model plant Arabidopsis thaliana has 21 formin-encoding loci, including 10 Class II members. In this study, we analyze the subcellular localization of two A. thaliana Class II formins exhibiting typical domain organization, the so far uncharacterized formin AtFH13 (At5g58160) and its distant homolog AtFH14 (At1g31810), previously reported to bind microtubules. Fluorescent protein-tagged full length formins and their individual domains were transiently expressed in Nicotiana benthamiana leaves under the control of a constitutive promoter and their subcellular localization (including co-localization with cytoskeletal structures and the endoplasmic reticulum) was examined using confocal microscopy. While the two formins exhibit distinct and only partially overlapping localization patterns, they both associate with microtubules via the conserved formin homology 2 (FH2) domain and with the periphery of the endoplasmic reticulum, at least in part via the N-terminal PTEN (Phosphatase and Tensin)-like domain. Surprisingly, FH2 domains of AtFH13 and AtFH14 can form heterodimers in the yeast two-hybrid assay-a first case of potentially biologically relevant formin heterodimerization mediated solely by the FH2 domain.
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Affiliation(s)
| | | | | | | | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Prague, Czech Republic; (E.K.); (A.B.F.); (L.S.); (S.P.)
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18
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Caillaud MC. Anionic Lipids: A Pipeline Connecting Key Players of Plant Cell Division. FRONTIERS IN PLANT SCIENCE 2019; 10:419. [PMID: 31110508 PMCID: PMC6499208 DOI: 10.3389/fpls.2019.00419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/19/2019] [Indexed: 05/23/2023]
Abstract
How cells position their division plane is a critical component of cell division. Indeed, it defines whether the two daughter cells divide symmetrically (with equal volumes) or not, and as such is critical for cell differentiation and lineage specification across eukaryotes. However, oriented cell divisions are of special significance for organisms with cell walls, such as plants, because their cells are embedded and cannot relocate. Correctly positioning the division plane is therefore of prevailing importance in plants, as it controls not only the occurrence of asymmetric cell division, but also tissue morphogenesis and organ integrity. While cytokinesis is executed in radically different manners in animals and plants, they both rely on the dynamic interplay between the cytoskeleton and membrane trafficking to precisely deliver molecular components to the future site of cell division. Recent research has shown that strict regulation of the levels and distribution of anionic lipids, which are minor components of the cell membrane's lipids, is required for successful cytokinesis in non-plant organisms. This review focused on the recent evidence pointing to whether such signaling lipids have roles in plant cell division.
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Affiliation(s)
- Marie-Cécile Caillaud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
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19
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Zhang S, Wang C, Xie M, Liu J, Kong Z, Su H. Actin Bundles in The Pollen Tube. Int J Mol Sci 2018; 19:ijms19123710. [PMID: 30469514 PMCID: PMC6321563 DOI: 10.3390/ijms19123710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.
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Affiliation(s)
- Shujuan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Chunbo Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Min Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Jinyu Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Zhe Kong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
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20
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Arabidopsis class I formins control membrane-originated actin polymerization at pollen tube tips. PLoS Genet 2018; 14:e1007789. [PMID: 30418966 PMCID: PMC6258422 DOI: 10.1371/journal.pgen.1007789] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 11/26/2018] [Accepted: 10/25/2018] [Indexed: 12/17/2022] Open
Abstract
A population of dynamic apical actin filaments is required for rapid polarized pollen tube growth. However, the cellular mechanisms driving their assembly remain incompletely understood. It was postulated that formin is a major player in nucleating apical actin assembly, but direct genetic and cytological evidence remains to be firmly established. Here we found that both Arabidopsis formin 3 (AtFH3) and formin 5 (AtFH5) are involved in the regulation of apical actin polymerization and actin array construction in pollen tubes, with AtFH3 playing a more dominant role. We found that both formins have plasma membrane (PM) localization signals but exhibit distinct PM localization patterns in the pollen tube, and loss of their function reduces the amount of apical actin filaments. Live-cell imaging revealed that the reduction in filamentous actin is very likely due to the decrease in filament elongation. Furthermore, we found that the rate of tip-directed vesicle transport is reduced and the pattern of apical vesicle accumulation is altered in formin loss-of-function mutant pollen tubes, which explains to some extent the reduction in pollen tube elongation. Thus, we provide direct genetic and cytological evidence showing that formin is an important player in nucleating actin assembly from the PM at pollen tube tips. Actin polymerization has been implicated in the regulation of rapid polarized pollen tube growth. The important role of actin polymerization is well appreciated, but the mechanisms that regulate rapid actin polymerization in pollen tubes remain incompletely understood. It was postulated that one of the major actin polymerization pathways in pollen tubes involves formin/profilin modules. However, direct genetic and cytological evidence is still required to support the role of formin in this framework. Using state-of-the-art live-cell imaging in combination with reverse genetic approaches, we demonstrate here that two class I formins, Arabidopsis formin 3 (AtFH3) and formin 5 (AtFH5), are involved in the regulation of apical actin polymerization and actin array construction in pollen tubes. In support of the role of AtFH3 and AtFH5 in regulating membrane-originated apical actin polymerization, we found that both of them are localized to the plasma membrane (PM) at pollen tube tips. Live-cell imaging revealed that the reduction in filamentous actin is very likely due to the decrease in elongation of actin filaments originating from the apical membrane. We also found that AtFH3 and AtFH5 exhibit distinct PM localization patterns in the pollen tube, suggesting that they might have distinct roles in regulating actin polymerization in pollen tubes. Our study provides direct genetic and cytological evidence that formins act as important players in regulating apical actin assembly in pollen tubes.
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21
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Diao M, Ren S, Wang Q, Qian L, Shen J, Liu Y, Huang S. Arabidopsis formin 2 regulates cell-to-cell trafficking by capping and stabilizing actin filaments at plasmodesmata. eLife 2018; 7:e36316. [PMID: 30113309 PMCID: PMC6126924 DOI: 10.7554/elife.36316] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 08/15/2018] [Indexed: 11/13/2022] Open
Abstract
Here, we demonstrate that Arabidopsis thaliana Formin 2 (AtFH2) localizes to plasmodesmata (PD) through its transmembrane domain and is required for normal intercellular trafficking. Although loss-of-function atfh2 mutants have no overt developmental defect, PD's permeability and sensitivity to virus infection are increased in atfh2 plants. Interestingly, AtFH2 functions in a partially redundant manner with its closest homolog AtFH1, which also contains a PD localization signal. Strikingly, targeting of Class I formins to PD was also confirmed in rice, suggesting that the involvement of Class I formins in regulating actin dynamics at PD may be evolutionarily conserved in plants. In vitro biochemical analysis showed that AtFH2 fails to nucleate actin assembly but caps and stabilizes actin filaments. We also demonstrate that the interaction between AtFH2 and actin filaments is crucial for its function in vivo. These data allow us to propose that AtFH2 regulates PD's permeability by anchoring actin filaments to PD.
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Affiliation(s)
- Min Diao
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- Institute of Botany, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Sulin Ren
- Institute of Botany, Chinese Academy of SciencesBeijingChina
| | - Qiannan Wang
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Lichao Qian
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life SciencesTsinghua UniversityBeijingChina
| | - Jiangfeng Shen
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Yule Liu
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life SciencesTsinghua UniversityBeijingChina
| | - Shanjin Huang
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
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22
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Sassmann S, Rodrigues C, Milne SW, Nenninger A, Allwood E, Littlejohn GR, Talbot NJ, Soeller C, Davies B, Hussey PJ, Deeks MJ. An Immune-Responsive Cytoskeletal-Plasma Membrane Feedback Loop in Plants. Curr Biol 2018; 28:2136-2144.e7. [PMID: 29937351 PMCID: PMC6041470 DOI: 10.1016/j.cub.2018.05.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 03/21/2018] [Accepted: 05/04/2018] [Indexed: 11/20/2022]
Abstract
Cell wall appositions (CWAs) are produced reactively by the plant immune system to arrest microbial invasion through the local inversion of plant cell growth. This process requires the controlled invagination of the plasma membrane (PM) in coordination with the export of barrier material to the volume between the plant PM and cell wall. Plant actin dynamics are essential to this response, but it remains unclear how exocytosis and the cytoskeleton are linked in space and time to form functional CWAs. Here, we show that actin-dependent trafficking to immune response sites of Arabidopsis thaliana delivers membrane-integrated FORMIN4, which in turn contributes to local cytoskeletal dynamics. Total internal reflection fluorescence (TIRF) microscopy combined with controlled induction of FORMIN4-GFP expression reveals a dynamic population of vesicular bodies that accumulate to form clusters at the PM through an actin-dependent process. Deactivation of FORMIN4 and its close homologs partially compromises subsequent defense and alters filamentous actin (F-actin) distribution at mature CWAs. The localization of FORMIN4 is stable and segregated from the dynamic traffic of the endosomal network. Moreover, the tessellation of FORMIN4 at the PM with meso-domains of PEN3 reveals a fine spatial segregation of destinations for actin-dependent immunity cargo. Together, our data suggest a model where FORMIN4 is a spatial feedback element in a multi-layered, temporally defined sequence of cytoskeletal response. This positional feedback makes a significant contribution to the distribution of actin filaments at the dynamic CWA boundary and to the outcomes of pre-invasion defense.
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Affiliation(s)
- Stefan Sassmann
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | | | - Stephen W Milne
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Anja Nenninger
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Ellen Allwood
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | | | | | - Christian Soeller
- Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Brendan Davies
- School of Biology, University of Leeds, Miall Building, Leeds LS2 9JT, UK
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Michael J Deeks
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK; Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
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23
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Wang P, Hawkins TJ, Hussey PJ. Connecting membranes to the actin cytoskeleton. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:71-76. [PMID: 28779654 DOI: 10.1016/j.pbi.2017.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/13/2017] [Indexed: 05/10/2023]
Abstract
In plants, the actin cytoskeleton plays a major role in organelle movement, cargo transport, maintaining cell polarity and controlling the morphogenesis of endomembrane systems. All of these events require a direct connection between membrane structures and the cytoskeleton. Our knowledge in this field has been greatly advanced by a few recent discoveries including the identification of the plant specific NETWORKED family of proteins, which can mediate such linkages. Other proteins that are known to regulate actin nucleation and polymerization are also likely to be involved, but many key questions still remain unanswered. In this paper, we will focus on recent research on the interfaces between the actin cytoskeleton and membranes of the endoplasmic reticulum, the vacuole and autophagosomes.
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Affiliation(s)
- Pengwei Wang
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Tim J Hawkins
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
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24
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Tolmie F, Poulet A, McKenna J, Sassmann S, Graumann K, Deeks M, Runions J. The cell wall of Arabidopsis thaliana influences actin network dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4517-4527. [PMID: 28981774 DOI: 10.1093/jxb/erx269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In plant cells, molecular connections link the cell wall-plasma membrane-actin cytoskeleton to form a continuum. It is hypothesized that the cell wall provides stable anchor points around which the actin cytoskeleton remodels. Here we use live cell imaging of fluorescently labelled marker proteins to quantify the organization and dynamics of the actin cytoskeleton and to determine the impact of disrupting connections within the continuum. Labelling of the actin cytoskeleton with green fluorescent protein (GFP)-fimbrin actin-binding domain 2 (FABD2) resulted in a network composed of fine filaments and thicker bundles that appeared as a highly dynamic remodelling meshwork. This differed substantially from the GFP-Lifeact-labelled network that appeared much more sparse with thick bundles that underwent 'simple movement', in which the bundles slightly change position, but in such a manner that the structure of the network was not substantially altered during the time of observation. Label-dependent differences in actin network morphology and remodelling necessitated development of two new image analysis techniques. The first of these, 'pairwise image subtraction', was applied to measurement of the more rapidly remodelling actin network labelled with GFP-FABD2, while the second, 'cumulative fluorescence intensity', was used to measure bulk remodelling of the actin cytoskeleton when labelled with GFP-Lifeact. In each case, these analysis techniques show that the actin cytoskeleton has a decreased rate of bulk remodelling when the cell wall-plasma membrane-actin continuum is disrupted either by plasmolysis or with isoxaben, a drug that specifically inhibits cellulose deposition. Changes in the rate of actin remodelling also affect its functionality, as observed by alteration in Golgi body motility.
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Affiliation(s)
- Frances Tolmie
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
| | - Axel Poulet
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
| | - Joseph McKenna
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
| | - Stefan Sassmann
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Katja Graumann
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
| | - Michael Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - John Runions
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
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25
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Wang M, Tu L, Lin M, Lin Z, Wang P, Yang Q, Ye Z, Shen C, Li J, Zhang L, Zhou X, Nie X, Li Z, Guo K, Ma Y, Huang C, Jin S, Zhu L, Yang X, Min L, Yuan D, Zhang Q, Lindsey K, Zhang X. Asymmetric subgenome selection and cis-regulatory divergence during cotton domestication. Nat Genet 2017; 49:579-587. [PMID: 28263319 DOI: 10.1038/ng.3807] [Citation(s) in RCA: 269] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/10/2017] [Indexed: 12/16/2022]
Abstract
Comparative population genomics offers an excellent opportunity for unraveling the genetic history of crop domestication. Upland cotton (Gossypium hirsutum) has long been an important economic crop, but a genome-wide and evolutionary understanding of the effects of human selection is lacking. Here, we describe a variation map for 352 wild and domesticated cotton accessions. We scanned 93 domestication sweeps occupying 74 Mb of the A subgenome and 104 Mb of the D subgenome, and identified 19 candidate loci for fiber-quality-related traits through a genome-wide association study. We provide evidence showing asymmetric subgenome domestication for directional selection of long fibers. Global analyses of DNase I-hypersensitive sites and 3D genome architecture, linking functional variants to gene transcription, demonstrate the effects of domestication on cis-regulatory divergence. This study provides new insights into the evolution of gene organization, regulation and adaptation in a major crop, and should serve as a rich resource for genome-based cotton improvement.
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Affiliation(s)
- Maojun Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Lili Tu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Min Lin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.,Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Zhongxu Lin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Pengcheng Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Qingyong Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.,Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Zhengxiu Ye
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Chao Shen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jianying Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Lin Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Xiaolin Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Xinhui Nie
- Key Laboratory of Oasis Eco-agriculture of the Xinjiang Production and Construction Corps, College of Agronomy, Shihezi University, Shihezi, China
| | - Zhonghua Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Kai Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yizan Ma
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Cong Huang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Shuangxia Jin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Longfu Zhu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Xiyan Yang
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ling Min
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Daojun Yuan
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qinghua Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Keith Lindsey
- Department of Biosciences, Durham University, Durham, UK
| | - Xianlong Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
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26
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Fan G, Niu S, Zhao Z, Deng M, Xu E, Wang Y, Yang L. Identification of microRNAs and their targets in Paulownia fortunei plants free from phytoplasma pathogen after methyl methane sulfonate treatment. Biochimie 2016; 127:271-80. [PMID: 27328782 DOI: 10.1016/j.biochi.2016.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 06/15/2016] [Indexed: 12/28/2022]
Abstract
MicroRNAs (miRNAs) play major roles in plant responses to various biotic and abiotic stresses by regulating gene expression at the transcriptional and post-transcriptional levels. Paulownia witches' broom (PaWB) disease caused by phytoplasmas reduces Paulownia production worldwide. In this study, we investigated the miRNA-mediated plant response to PaWB phytoplasma by Illumina sequencing and degradome analysis of Paulownia fortunei small RNAs (sRNAs). The sRNA and degradome libraries were constructed from healthy and diseased P. fortunei plants and the plants free from phytoplasma pathogen after 60 mg L(-1) methyl methane sulfonate treatment. A total of 96 P. fortunei-conserved miRNAs and 83 putative novel miRNAs were identified. Among them, 37 miRNAs (17 conserved, 20 novel) were found to be differentially expressed in response to PaWB phytoplasma infection. In addition, 114 target genes for 18 of the conserved miRNA families and 33 target genes for 15 of the novel miRNAs in P. fortunei were detected. The expression patterns of 14 of the PaWB phytoplasma-responsive miRNAs and 12 target genes were determined by quantitative real-time polymerase chain reaction (qPCR) experiments. A functional analysis of the miRNA targets indicated that these targeted genes may regulate transcription, stress response, nitrogen metabolism, and various other activities. Our results will help identify the potential roles of miRNAs involved in protecting P. fortunei from diseases.
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Affiliation(s)
- Guoqiang Fan
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China.
| | - Suyan Niu
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
| | - Zhenli Zhao
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
| | - Minjie Deng
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
| | - Enkai Xu
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
| | - Yuanlong Wang
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
| | - Lu Yang
- Institute of Paulownia, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China; College of Forestry, Henan Agricultural University, 450002 Zhengzhou, Henan, PR China
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27
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Bioinformatic Identification and Analysis of Extensins in the Plant Kingdom. PLoS One 2016; 11:e0150177. [PMID: 26918442 PMCID: PMC4769139 DOI: 10.1371/journal.pone.0150177] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/10/2016] [Indexed: 12/02/2022] Open
Abstract
Extensins (EXTs) are a family of plant cell wall hydroxyproline-rich glycoproteins (HRGPs) that are implicated to play important roles in plant growth, development, and defense. Structurally, EXTs are characterized by the repeated occurrence of serine (Ser) followed by three to five prolines (Pro) residues, which are hydroxylated as hydroxyproline (Hyp) and glycosylated. Some EXTs have Tyrosine (Tyr)-X-Tyr (where X can be any amino acid) motifs that are responsible for intramolecular or intermolecular cross-linkings. EXTs can be divided into several classes: classical EXTs, short EXTs, leucine-rich repeat extensins (LRXs), proline-rich extensin-like receptor kinases (PERKs), formin-homolog EXTs (FH EXTs), chimeric EXTs, and long chimeric EXTs. To guide future research on the EXTs and understand evolutionary history of EXTs in the plant kingdom, a bioinformatics study was conducted to identify and classify EXTs from 16 fully sequenced plant genomes, including Ostreococcus lucimarinus, Chlamydomonas reinhardtii, Volvox carteri, Klebsormidium flaccidum, Physcomitrella patens, Selaginella moellendorffii, Pinus taeda, Picea abies, Brachypodium distachyon, Zea mays, Oryza sativa, Glycine max, Medicago truncatula, Brassica rapa, Solanum lycopersicum, and Solanum tuberosum, to supplement data previously obtained from Arabidopsis thaliana and Populus trichocarpa. A total of 758 EXTs were newly identified, including 87 classical EXTs, 97 short EXTs, 61 LRXs, 75 PERKs, 54 FH EXTs, 38 long chimeric EXTs, and 346 other chimeric EXTs. Several notable findings were made: (1) classical EXTs were likely derived after the terrestrialization of plants; (2) LRXs, PERKs, and FHs were derived earlier than classical EXTs; (3) monocots have few classical EXTs; (4) Eudicots have the greatest number of classical EXTs and Tyr-X-Tyr cross-linking motifs are predominantly in classical EXTs; (5) green algae have no classical EXTs but have a number of long chimeric EXTs that are absent in embryophytes. Furthermore, phylogenetic analysis was conducted of LRXs, PERKs and FH EXTs, which shed light on the evolution of three EXT classes.
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28
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Shevchenko G. Participation of proteins binding both actin filaments and microtubules in higher plant cell growth. CYTOL GENET+ 2015. [DOI: 10.3103/s009545271504009x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Gavrin A, Jansen V, Ivanov S, Bisseling T, Fedorova E. ARP2/3-Mediated Actin Nucleation Associated With Symbiosome Membrane Is Essential for the Development of Symbiosomes in Infected Cells of Medicago truncatula Root Nodules. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:605-14. [PMID: 25608180 DOI: 10.1094/mpmi-12-14-0402-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The nitrogen-fixing rhizobia in the symbiotic infected cells of root nodules are kept in membrane compartments derived from the host cell plasma membrane, forming what are known as symbiosomes. These are maintained as individual units, with mature symbiosomes having a specific radial position in the host cell cytoplasm. The mechanisms that adapt the host cell architecture to accommodate intracellular bacteria are not clear. The intracellular organization of any cell depends heavily on the actin cytoskeleton. Dynamic rearrangement of the actin cytoskeleton is crucial for cytoplasm organization and intracellular trafficking of vesicles and organelles. A key component of the actin cytoskeleton rearrangement is the ARP2/3 complex, which nucleates new actin filaments and forms branched actin networks. To clarify the role of the ARP2/3 complex in the development of infected cells and symbiosomes, we analyzed the pattern of actin microfilaments and the functional role of ARP3 in Medicago truncatula root nodules. In infected cells, ARP3 protein and actin were spatially associated with maturing symbiosomes. Partial ARP3 silencing causes defects in symbiosome development; in particular, ARP3 silencing disrupts the final differentiation steps in functional maturation into nitrogen-fixing units.
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Affiliation(s)
- Aleksandr Gavrin
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Veerle Jansen
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Sergey Ivanov
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Ton Bisseling
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Elena Fedorova
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
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30
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Qu X, Jiang Y, Chang M, Liu X, Zhang R, Huang S. Organization and regulation of the actin cytoskeleton in the pollen tube. FRONTIERS IN PLANT SCIENCE 2015; 5:786. [PMID: 25620974 PMCID: PMC4287052 DOI: 10.3389/fpls.2014.00786] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/17/2014] [Indexed: 05/18/2023]
Abstract
Proper organization of the actin cytoskeleton is crucial for pollen tube growth. However, the precise mechanisms by which the actin cytoskeleton regulates pollen tube growth remain to be further elucidated. The functions of the actin cytoskeleton are dictated by its spatial organization and dynamics. However, early observations of the distribution of actin filaments at the pollen tube apex were quite perplexing, resulting in decades of controversial debate. Fortunately, due to improvements in fixation regimens for staining actin filaments in fixed pollen tubes, as well as the adoption of appropriate markers for visualizing actin filaments in living pollen tubes, this issue has been resolved and has given rise to the consensus view of the spatial distribution of actin filaments throughout the entire pollen tube. Importantly, recent descriptions of the dynamics of individual actin filaments in the apical region have expanded our understanding of the function of actin in regulation of pollen tube growth. Furthermore, careful documentation of the function and mode of action of several actin-binding proteins expressed in pollen have provided novel insights into the regulation of actin spatial distribution and dynamics. In the current review, we summarize our understanding of the organization, dynamics, and regulation of the actin cytoskeleton in the pollen tube.
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Affiliation(s)
- Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua UniversityBeijing, China
| | - Yuxiang Jiang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Ming Chang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Xiaonan Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
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31
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Cvrčková F, Oulehlová D, Žárský V. Formins: linking cytoskeleton and endomembranes in plant cells. Int J Mol Sci 2014; 16:1-18. [PMID: 25546384 PMCID: PMC4307232 DOI: 10.3390/ijms16010001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/17/2014] [Indexed: 02/07/2023] Open
Abstract
The cytoskeleton plays a central part in spatial organization of the plant cytoplasm, including the endomebrane system. However, the mechanisms involved are so far only partially understood. Formins (FH2 proteins), a family of evolutionarily conserved proteins sharing the FH2 domain whose dimer can nucleate actin, mediate the co-ordination between actin and microtubule cytoskeletons in multiple eukaryotic lineages including plants. Moreover, some plant formins contain transmembrane domains and participate in anchoring cytoskeletal structures to the plasmalemma, and possibly to other membranes. Direct or indirect membrane association is well documented even for some fungal and metazoan formins lacking membrane insertion motifs, and FH2 proteins have been shown to associate with endomembranes and modulate their dynamics in both fungi and metazoans. Here we summarize the available evidence suggesting that formins participate in membrane trafficking and endomembrane, especially ER, organization also in plants. We propose that, despite some methodological pitfalls inherent to in vivo studies based on (over)expression of truncated and/or tagged proteins, formins are beginning to emerge as candidates for the so far somewhat elusive link between the plant cytoskeleton and the endomembrane system.
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Affiliation(s)
- Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, 128 43 Prague 2, Czech Republic.
| | - Denisa Oulehlová
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, 128 43 Prague 2, Czech Republic.
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, 128 43 Prague 2, Czech Republic.
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32
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McKenna JF, Tolmie AF, Runions J. Across the great divide: the plant cell surface continuum. CURRENT OPINION IN PLANT BIOLOGY 2014; 22:132-140. [PMID: 25460078 DOI: 10.1016/j.pbi.2014.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/21/2014] [Accepted: 11/01/2014] [Indexed: 06/04/2023]
Abstract
The plant cell wall, plasma membrane and cytoskeleton exist as a cell surface continuum. This interconnection of organelles forms the interface between the plant cell and the external environment and is important for detecting the presence of a diverse range of stimuli. A plethora of plasma membrane microdomains with putative roles in membrane localized enzymatic or signalling processes have been described. While regulation of cell wall composition is defined by proteins within the plasma membrane, the cell wall has been shown to have an anchoring role on plasma membrane proteins which affects their lateral mobility. This interplay between plasma membrane and cell wall components is necessary for plasma membrane microdomain function. Actin and microtubule cytoskeletons are also involved in maintenance and function of the cell surface continuum. Investigation of the interactions between organellar components of this mechanism are important if we are to understand how cells respond to external signals.
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Affiliation(s)
- Joseph F McKenna
- Plant Cell Biology, Oxford Brookes University, Department of Biological & Medical Sciences, Gipsy Lane, Oxford OX3 0BP, UK
| | - A Frances Tolmie
- Plant Cell Biology, Oxford Brookes University, Department of Biological & Medical Sciences, Gipsy Lane, Oxford OX3 0BP, UK
| | - John Runions
- Plant Cell Biology, Oxford Brookes University, Department of Biological & Medical Sciences, Gipsy Lane, Oxford OX3 0BP, UK.
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33
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Zhao C, Liu C, Hogue CWV, Low BC. A cooperative jack model of random coil-to-elongation transition of the FH1 domain by profilin binding explains formin motor behavior in actin polymerization. FEBS Lett 2014; 588:2288-93. [PMID: 24861497 DOI: 10.1016/j.febslet.2014.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/28/2014] [Accepted: 05/06/2014] [Indexed: 11/24/2022]
Abstract
Filopodia are essential for the development of neuronal growth cones, cell polarity and cell migration. Their protrusions are powered by the polymerization of actin filaments linked to the plasma membrane, catalyzed by formin proteins. The acceleration of polymerization depends on the number of profilin-actins binding with the formin-FH1 domain. Biophysical characterization of the disordered formin-FH1 domain remains a challenge. We analyzed the conformational distribution of the diaphanous-related formin mDia1-FH1 bound with one to six profilins. We found a coil-to-elongation transition in the FH1 domain. We propose a cooperative "jack" model for the Formin-Homology-1 (FH1) domain of formins stacked by profilin-actins.
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Affiliation(s)
- Chen Zhao
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| | - Chengcheng Liu
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668, Singapore
| | - Christopher W V Hogue
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Boon Chuan Low
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore; Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
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34
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De Storme N, Geelen D. The impact of environmental stress on male reproductive development in plants: biological processes and molecular mechanisms. PLANT, CELL & ENVIRONMENT 2014; 37:1-18. [PMID: 23731015 PMCID: PMC4280902 DOI: 10.1111/pce.12142] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/30/2013] [Accepted: 05/08/2013] [Indexed: 05/18/2023]
Abstract
In plants, male reproductive development is extremely sensitive to adverse climatic environments and (a)biotic stress. Upon exposure to stress, male gametophytic organs often show morphological, structural and metabolic alterations that typically lead to meiotic defects or premature spore abortion and male reproductive sterility. Depending on the type of stress involved (e.g. heat, cold, drought) and the duration of stress exposure, the underlying cellular defect is highly variable and either involves cytoskeletal alterations, tapetal irregularities, altered sugar utilization, aberrations in auxin metabolism, accumulation of reactive oxygen species (ROS; oxidative stress) or the ectopic induction of programmed cell death (PCD). In this review, we present the critically stress-sensitive stages of male sporogenesis (meiosis) and male gametogenesis (microspore development), and discuss the corresponding biological processes involved and the resulting alterations in male reproduction. In addition, this review also provides insights into the molecular and/or hormonal regulation of the environmental stress sensitivity of male reproduction and outlines putative interaction(s) between the different processes involved.
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Affiliation(s)
- Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Coupure Links, 653, B-9000, Ghent, Belgium
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35
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Cvrčková F. Formins and membranes: anchoring cortical actin to the cell wall and beyond. FRONTIERS IN PLANT SCIENCE 2013; 4:436. [PMID: 24204371 PMCID: PMC3817587 DOI: 10.3389/fpls.2013.00436] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/13/2013] [Indexed: 05/03/2023]
Abstract
Formins are evolutionarily conserved eukaryotic proteins participating in actin and microtubule organization. Land plants have three formin clades, with only two - Class I and II - present in angiosperms. Class I formins are often transmembrane proteins, residing at the plasmalemma and anchoring the cortical cytoskeleton across the membrane to the cell wall, while Class II formins possess a PTEN-related membrane-binding domain. Lower plant Class III and non-plant formins usually contain domains predicted to bind RHO GTPases that are membrane-associated. Thus, some kind of membrane anchorage appears to be a common formin feature. Direct interactions between various non-plant formins and integral or peripheral membrane proteins have indeed been reported, with varying mechanisms and biological implications. Besides of summarizing new data on Class I and Class II formin-membrane relationships, this review surveys such "non-classical" formin-membrane interactions and examines which, if any, of them may be evolutionarily conserved and operating also in plants. FYVE, SH3 and BAR domain-containing proteins emerge as possible candidates for such conserved membrane-associated formin partners.
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Affiliation(s)
- Fatima Cvrčková
- *Correspondence: Fatima Cvrčková, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43, Prague, Czech Republic e-mail:
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36
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Jimenez-Lopez JC, Rodríguez-García MI, Alché JD. Analysis of the effects of polymorphism on pollen profilin structural functionality and the generation of conformational, T- and B-cell epitopes. PLoS One 2013; 8:e76066. [PMID: 24146818 PMCID: PMC3798325 DOI: 10.1371/journal.pone.0076066] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/19/2013] [Indexed: 12/17/2022] Open
Abstract
An extensive polymorphism analysis of pollen profilin, a fundamental regulator of the actin cytoskeleton dynamics, has been performed with a major focus in 3D-folding maintenance, changes in the 2-D structural elements, surface residues involved in ligands-profilin interactions and functionality, and the generation of conformational and lineal B- and T-cell epitopes variability. Our results revealed that while the general fold is conserved among profilins, substantial structural differences were found, particularly affecting the special distribution and length of different 2-D structural elements (i.e. cysteine residues), characteristic loops and coils, and numerous micro-heterogeneities present in fundamental residues directly involved in the interacting motifs, and to some extension these residues nearby to the ligand-interacting areas. Differential changes as result of polymorphism might contribute to generate functional variability among the plethora of profilin isoforms present in the olive pollen from different genetic background (olive cultivars), and between plant species, since biochemical interacting properties and binding affinities to natural ligands may be affected, particularly the interactions with different actin isoforms and phosphoinositides lipids species. Furthermore, conspicuous variability in lineal and conformational epitopes was found between profilins belonging to the same olive cultivar, and among different cultivars as direct implication of sequences polymorphism. The variability of the residues taking part of IgE-binding epitopes might be the final responsible of the differences in cross-reactivity among olive pollen cultivars, among pollen and plant-derived food allergens, as well as between distantly related pollen species, leading to a variable range of allergy reactions among atopic patients. Identification and analysis of commonly shared and specific epitopes in profilin isoforms is essential to gain knowledge about the interacting surface of these epitopes, and for a better understanding of immune responses, helping design and development of rational and effective immunotherapy strategies for the treatment of allergy diseases.
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MESH Headings
- Amino Acid Sequence
- Antigens, Plant/chemistry
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/classification
- Epitopes, B-Lymphocyte/genetics
- Epitopes, B-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/classification
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- Food Hypersensitivity/immunology
- Humans
- Models, Molecular
- Molecular Sequence Data
- Olea/chemistry
- Phylogeny
- Plant Proteins/chemistry
- Pollen/chemistry
- Polymorphism, Genetic/immunology
- Profilins/chemistry
- Profilins/classification
- Profilins/genetics
- Profilins/immunology
- Protein Structure, Tertiary
- Sequence Alignment
- Structural Homology, Protein
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Affiliation(s)
- Jose C. Jimenez-Lopez
- Department of Biochemistry, Cell and Molecular Biology of plants, Estación Experimental del Zaidín (EEZ), High Council for Scientific Research (CSIC), Granada, Spain
- * E-mail: (JCJL); (JDA)
| | - María I. Rodríguez-García
- Department of Biochemistry, Cell and Molecular Biology of plants, Estación Experimental del Zaidín (EEZ), High Council for Scientific Research (CSIC), Granada, Spain
| | - Juan D. Alché
- Department of Biochemistry, Cell and Molecular Biology of plants, Estación Experimental del Zaidín (EEZ), High Council for Scientific Research (CSIC), Granada, Spain
- * E-mail: (JCJL); (JDA)
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37
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Vaškovičová K, Žárský V, Rösel D, Nikolič M, Buccione R, Cvrčková F, Brábek J. Invasive cells in animals and plants: searching for LECA machineries in later eukaryotic life. Biol Direct 2013; 8:8. [PMID: 23557484 PMCID: PMC3663805 DOI: 10.1186/1745-6150-8-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 03/21/2013] [Indexed: 02/08/2023] Open
Abstract
Invasive cell growth and migration is usually considered a specifically metazoan phenomenon. However, common features and mechanisms of cytoskeletal rearrangements, membrane trafficking and signalling processes contribute to cellular invasiveness in organisms as diverse as metazoans and plants – two eukaryotic realms genealogically connected only through the last common eukaryotic ancestor (LECA). By comparing current understanding of cell invasiveness in model cell types of both metazoan and plant origin (invadopodia of transformed metazoan cells, neurites, pollen tubes and root hairs), we document that invasive cell behavior in both lineages depends on similar mechanisms. While some superficially analogous processes may have arisen independently by convergent evolution (e.g. secretion of substrate- or tissue-macerating enzymes by both animal and plant cells), at the heart of cell invasion is an evolutionarily conserved machinery of cellular polarization and oriented cell mobilization, involving the actin cytoskeleton and the secretory pathway. Its central components - small GTPases (in particular RHO, but also ARF and Rab), their specialized effectors, actin and associated proteins, the exocyst complex essential for polarized secretion, or components of the phospholipid- and redox- based signalling circuits (inositol-phospholipid kinases/PIP2, NADPH oxidases) are aparently homologous among plants and metazoans, indicating that they were present already in LECA. Reviewer: This article was reviewed by Arcady Mushegian, Valerian Dolja and Purificacion Lopez-Garcia.
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Affiliation(s)
- Katarína Vaškovičová
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43, Prague 2, Czech Republic
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38
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Yanagisawa M, Zhang C, Szymanski DB. ARP2/3-dependent growth in the plant kingdom: SCARs for life. FRONTIERS IN PLANT SCIENCE 2013; 4:166. [PMID: 23802001 PMCID: PMC3689024 DOI: 10.3389/fpls.2013.00166] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 05/12/2013] [Indexed: 05/18/2023]
Abstract
In the human experience SCARs (suppressor of cAMP receptors) are permanent reminders of past events, not always based on bad decisions, but always those in which an interplay of opposing forces leaves behind a clear record in the form of some permanent watery mark. During plant morphogenesis, SCARs are important proteins that reflect an unusual evolutionary outcome, in which the plant kingdom relies heavily on this single class of actin-related protein (ARP) 2/3 complex activator to dictate the time and place of actin filament nucleation. This unusually simple arrangement may serve as a permanent reminder that cell shape control in plants is fundamentally different from that of crawling cells in mammals that use the power of actin polymerization to define and maintain cell shape. In plant cells, actin filaments indirectly affect cell shape by determining the transport properties of organelles and cargo molecules that modulate the mechanical properties of the wall. It is becoming increasingly clear that polarized bundles of actin filaments operate at whole cell spatial scales to organize the cytoplasm and dictate the patterns of long-distance intracellular transport and secretion. The number of actin-binding proteins and actin filament nucleators that are known to participate in the process of actin network formation are rapidly increasing. In plants, formins and ARP2/3 are two important actin filament nucleators. This review will focus on ARP2/3, and the apparent reliance of most plant species on the SCAR/WAVE (WASP family verprolin homologous) regulatory complex as the sole pathway for ARP2/3 activation.
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Affiliation(s)
| | - Chunhua Zhang
- Department of Botany and Plant Sciences, University of CaliforniaRiverside, CA, USA
| | - Daniel B. Szymanski
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
- Department of Biological Sciences, Purdue UniversityWest Lafayette, IN, USA
- *Correspondence: Daniel B. Szymanski, Department of Agronomy, Purdue University, 1150 Lilly Hall of Life Sciences, West Lafayette, IN 47907-1150, USA e-mail:
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Rosero A, Žárský V, Cvrčková F. AtFH1 formin mutation affects actin filament and microtubule dynamics in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64. [PMID: 23202131 PMCID: PMC3542049 DOI: 10.1093/jxb/ers351] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plant cell growth and morphogenesis depend on remodelling of both actin and microtubule cytoskeletons. AtFH1 (At5g25500), the main housekeeping Arabidopsis formin, is targeted to membranes and known to nucleate and bundle actin. The effect of mutations in AtFH1 on root development and cytoskeletal dynamics was examined. Consistent with primarily actin-related formin function, fh1 mutants showed increased sensitivity to the actin polymerization inhibitor latrunculin B (LatB). LatB-treated mutants had thicker, shorter roots than wild-type plants. Reduced cell elongation and morphological abnormalities were observed in both trichoblasts and atrichoblasts. Fluorescently tagged cytoskeletal markers were used to follow cytoskeletal dynamics in wild-type and mutant plants using confocal microscopy and VAEM (variable-angle epifluorescence microscopy). Mutants exhibited more abundant but less dynamic F-actin bundles and more dynamic microtubules than wild-type seedlings. Treatment of wild-type seedlings with a formin inhibitor, SMIFH2, mimicked the root growth and cell expansion phenotypes and cytoskeletal structure alterations observed in fh1 mutants. The results suggest that besides direct effects on actin organization, the in vivo role of AtFH1 also includes modulation of microtubule dynamics, possibly mediated by actin-microtubule cross-talk.
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Affiliation(s)
- Amparo Rosero
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Praha 2, Czech Republic
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Praha 2, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 135, CZ 160 00 Prague 6, Czech Republic
| | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Praha 2, Czech Republic
- * To whom correspondence should be addressed. E-mail:
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Zheng Y, Xin H, Lin J, Liu CM, Huang S. An Arabidopsis class II formin, AtFH19, nucleates actin assembly, binds to the barbed end of actin filaments, and antagonizes the effect of AtFH1 on actin dynamics. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:800-13. [PMID: 22947203 DOI: 10.1111/j.1744-7909.2012.01160.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Formin is a major protein responsible for regulating the nucleation of actin filaments, and as such, it permits the cell to control where and when to assemble actin arrays. It is encoded by a multigene family comprising 21 members in Arabidopsis thaliana. The Arabidopsis formins can be separated into two phylogenetically-distinct classes: there are 11 class I formins and 10 class II formins. Significant questions remain unanswered regarding the molecular mechanism of actin nucleation and elongation stimulated by each formin isovariant, and how the different isovariants coordinate to regulate actin dynamics in cells. Here, we characterize a class II formin, AtFH19, biochemically. We found that AtFH19 retains all general properties of the formin family, including nucleation and barbed end capping activity. It can also generate actin filaments from a pool of actin monomers bound to profilin. However, both the nucleation and barbed end capping activities of AtFH19 are less efficient compared to those of another well-characterized formin, AtFH1. Interestingly, AtFH19 FH1FH2 competes with AtFH1 FH1FH2 in binding actin filament barbed ends, and inhibits the effect of AtFH1 FH1FH2 on actin. We thus propose a mechanism in which two quantitatively different formins coordinate to regulate actin dynamics by competing for actin filament barbed ends.
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Affiliation(s)
- Yiyan Zheng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
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41
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Cvrčková F. Formins: emerging players in the dynamic plant cell cortex. SCIENTIFICA 2012; 2012:712605. [PMID: 24278734 PMCID: PMC3820618 DOI: 10.6064/2012/712605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 09/16/2012] [Indexed: 05/11/2023]
Abstract
Formins (FH2 proteins) are an evolutionarily conserved family of eukaryotic proteins, sharing the common FH2 domain. While they have been, until recently, understood mainly as actin nucleators, formins are also engaged in various additional aspects of cytoskeletal organization and signaling, including, but not limited to, the crosstalk between the actin and microtubule networks. A surprising diversity of domain organizations has been discovered among the FH2 proteins, and specific domain setups have been found in plants. Seed plants have two clades of formins, one of them (Class I) containing mostly transmembrane proteins, while members of the other one (Class II) may be anchored to membranes via a putative membrane-binding domain related to the PTEN antioncogene. Thus, plant formins present good candidates for possible mediators of coordination of the cortical actin and microtubule cytoskeletons, as well as their attachment to the plasma membrane, that is, aspects of cell cortex organization likely to be important for cell and tissue morphogenesis. Although experimental studies of plant formin function are hampered by the large number of formin genes and their functional redundancy, recent experimental work has already resulted in some remarkable insights into the function of FH2 proteins in plants.
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Affiliation(s)
- Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 43 Prague, Czech Republic
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Redillas MCFR, Jeong JS, Kim YS, Jung H, Bang SW, Choi YD, Ha SH, Reuzeau C, Kim JK. The overexpression of OsNAC9 alters the root architecture of rice plants enhancing drought resistance and grain yield under field conditions. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:792-805. [PMID: 22551450 DOI: 10.1111/j.1467-7652.2012.00697.x] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Drought conditions limit agricultural production by preventing crops from reaching their genetically predetermined maximum yields. Here, we present the results of field evaluations of rice overexpressing OsNAC9, a member of the rice NAC domain family. Root-specific (RCc3) and constitutive (GOS2) promoters were used to overexpress OsNAC9 and produced the transgenic RCc3:OsNAC9 and GOS2:OsNAC9 plants. Field evaluations over two cultivating seasons showed that grain yields of the RCc3:OsNAC9 and the GOS2:OsNAC9 plants were increased by 13%-18% and 13%-32% under normal conditions, respectively. Under drought conditions, RCc3:OsNAC9 plants showed an increased grain yield of 28%-72%, whilst the GOS2:OsNAC9 plants remained unchanged. Both transgenic lines exhibited altered root architecture involving an enlarged stele and aerenchyma. The aerenchyma of RCc3:OsNAC9 roots was enlarged to a greater extent than those of GOS2:OsNAC9 and non-transgenic (NT) roots, suggesting the importance of this phenotype for enhanced drought resistance. Microarray experiments identified 40 up-regulated genes by more than threefold (P < 0.01) in the roots of both transgenic lines. These included 9-cis-epoxycarotenoid dioxygenase, an ABA biosynthesis gene, calcium-transporting ATPase, a component of the Ca(2+) signalling pathway involved in cortical cell death and aerenchyma formation, cinnamoyl CoA reductase 1, a gene involved in lignin biosynthesis, and wall-associated kinases¸ genes involved in cell elongation and morphogenesis. Interestingly, O-methyltransferase, a gene necessary for barrier formation, was specifically up-regulated only in the RCc3:OsNAC9 roots. Such up-regulated genes that are commonly and specifically up-regulated in OsNAC9 transgenic roots may account for the altered root architecture conferring increased drought resistance phenotype.
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Affiliation(s)
- Mark C F R Redillas
- School of Biotechnology and Environmental Engineering, Myongji University, Yongin, Korea
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Thomas C. Bundling actin filaments from membranes: some novel players. FRONTIERS IN PLANT SCIENCE 2012; 3:188. [PMID: 22936939 PMCID: PMC3426786 DOI: 10.3389/fpls.2012.00188] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/01/2012] [Indexed: 05/04/2023]
Abstract
Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling.
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Affiliation(s)
- Clément Thomas
- Laboratory of Molecular and Cellular Oncology, Department of Oncology, Public Research Centre for Health (CRP-Santé)Luxembourg, Luxembourg
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44
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Wang J, Xue X, Ren H. New insights into the role of plant formins: regulating the organization of the actin and microtubule cytoskeleton. PROTOPLASMA 2012; 249 Suppl 2:S101-7. [PMID: 22215231 DOI: 10.1007/s00709-011-0368-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 12/13/2011] [Indexed: 05/03/2023]
Abstract
Formins are well-known as important regulators participating in the organization of the actin cytoskeleton in organisms. For many years in the past, research on plant formins is more difficult than that in other eukaryotic formins and is limited to class I formins. Nevertheless, positive progress has been made in plant formin research recently, especially the investigations on class II formins. New functions of plant formins are identified gradually, such as regulating cell division and affecting diffuse cell expansion. More significantly, plant formins are also verified to interact with microtubules in vivo and in vitro. They may probably function as linking proteins between microtubules and microfilaments to participate in various cellular processes.
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Affiliation(s)
- Jiaojiao Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing 100875, China
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45
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Pei W, Du F, Zhang Y, He T, Ren H. Control of the actin cytoskeleton in root hair development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 187:10-8. [PMID: 22404828 DOI: 10.1016/j.plantsci.2012.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 05/09/2023]
Abstract
The development of root hair includes four stages: bulge site selection, bulge formation, tip growth, and maturation. The actin cytoskeleton is involved in all of these stages and is organized into distinct arrangements in the different stages. In addition to the actin configuration, actin isoforms also play distinct roles in the different stages. The actin cytoskeleton is regulated by actin-binding proteins, such as formin, Arp2/3 complex, profilin, actin depolymerizing factor, and villin. Some upstream signals, i.e. calcium, phospholipids, and small GTPase regulate the activity of these actin-binding proteins to produce the proper actin configuration. We constructed a working model on how the actin cytoskeleton is controlled by actin-binding proteins and upstream signaling in root hair development based on the current literature: at the tip of hairs, actin polymerization appears to be facilitated by Arp2/3 complex that is activated by small GTPase, and profilin that is regulated by phosphatidylinositol 4,5-bisphosphate. Meanwhile, actin depolymerization and turnover are likely mediated by villin and actin depolymerizing factor, which are stimulated by calcium. At the shank, actin cables are produced by formin and villin. Under the complicated interaction, the actin cytoskeleton is controlled spatially and temporally during root hair development.
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Affiliation(s)
- Weike Pei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing 100875, China
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46
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Jimenez-Lopez JC, Morales S, Castro AJ, Volkmann D, Rodríguez-García MI, Alché JDD. Characterization of profilin polymorphism in pollen with a focus on multifunctionality. PLoS One 2012; 7:e30878. [PMID: 22348028 PMCID: PMC3279341 DOI: 10.1371/journal.pone.0030878] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 12/28/2011] [Indexed: 12/20/2022] Open
Abstract
Profilin, a multigene family involved in actin dynamics, is a multiple partners-interacting protein, as regard of the presence of at least of three binding domains encompassing actin, phosphoinositide lipids, and poly-L-proline interacting patches. In addition, pollen profilins are important allergens in several species like Olea europaea L. (Ole e 2), Betula pendula (Bet v 2), Phleum pratense (Phl p 12), Zea mays (Zea m 12) and Corylus avellana (Cor a 2). In spite of the biological and clinical importance of these molecules, variability in pollen profilin sequences has been poorly pointed out up until now. In this work, a relatively high number of pollen profilin sequences have been cloned, with the aim of carrying out an extensive characterization of their polymorphism among 24 olive cultivars and the above mentioned plant species. Our results indicate a high level of variability in the sequences analyzed. Quantitative intra-specific/varietal polymorphism was higher in comparison to inter-specific/cultivars comparisons. Multi-optional posttranslational modifications, e.g. phosphorylation sites, physicochemical properties, and partners-interacting functional residues have been shown to be affected by profilin polymorphism. As a result of this variability, profilins yielded a clear taxonomic separation between the five plant species. Profilin family multifunctionality might be inferred by natural variation through profilin isovariants generated among olive germplasm, as a result of polymorphism. The high variability might result in both differential profilin properties and differences in the regulation of the interaction with natural partners, affecting the mechanisms underlying the transmission of signals throughout signaling pathways in response to different stress environments. Moreover, elucidating the effect of profilin polymorphism in adaptive responses like actin dynamics, and cellular behavior, represents an exciting research goal for the future.
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Affiliation(s)
- Jose C. Jimenez-Lopez
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, High Council for Scientific Research, Granada, Spain
| | - Sonia Morales
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, High Council for Scientific Research, Granada, Spain
| | - Antonio J. Castro
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, High Council for Scientific Research, Granada, Spain
| | - Dieter Volkmann
- Institute of Cellular and Molecular Botany, Department of Plant Cell Biology, University of Bonn, Bonn, Germany
| | - María I. Rodríguez-García
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, High Council for Scientific Research, Granada, Spain
| | - Juan de D. Alché
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, High Council for Scientific Research, Granada, Spain
- * E-mail:
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Liu P, Qi M, Xue X, Ren H. Dynamics and functions of the actin cytoskeleton during the plant cell cycle. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s11434-011-4801-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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48
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Martinière A, Gayral P, Hawes C, Runions J. Building bridges: formin1 of Arabidopsis forms a connection between the cell wall and the actin cytoskeleton. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:354-65. [PMID: 21241388 DOI: 10.1111/j.1365-313x.2011.04497.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Actin microfilament (MF) organization and remodelling is critical to cell function. The formin family of actin binding proteins are involved in nucleating MFs in Arabidopsis thaliana. They all contain formin homology domains in the intracellular, C-terminal half of the protein that interacts with MFs. Formins in class I are usually targeted to the plasma membrane and this is true of Formin1 (AtFH1) of A. thaliana. In this study, we have investigated the extracellular domain of AtFH1 and we demonstrate that AtFH1 forms a bridge from the actin cytoskeleton, across the plasma membrane and is anchored within the cell wall. AtFH1 has a large, extracellular domain that is maintained by purifying selection and that contains four conserved regions, one of which is responsible for immobilising the protein. Protein anchoring within the cell wall is reduced in constructs that express truncations of the extracellular domain and in experiments in protoplasts without primary cell walls. The 18 amino acid proline-rich extracellular domain that is responsible for AtFH1 anchoring has homology with cell-wall extensins. We also have shown that anchoring of AtFH1 in the cell wall promotes actin bundling within the cell and that overexpression of AtFH1 has an inhibitory effect on organelle actin-dependant dynamics. Thus, the AtFH1 bridge provides stable anchor points for the actin cytoskeleton and is probably a crucial component of the signalling response and actin-remodelling mechanisms.
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Affiliation(s)
- Alexandre Martinière
- Department of Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford OX30BP, UK
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49
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Xue XH, Guo CQ, Du F, Lu QL, Zhang CM, Ren HY. AtFH8 is involved in root development under effect of low-dose latrunculin B in dividing cells. MOLECULAR PLANT 2011; 4:264-78. [PMID: 21307369 DOI: 10.1093/mp/ssq085] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Formins have been paid much attention for their potent nucleating activity. However, the connection between the in vivo functions of AtFHs (Arabidopsis thaliana formin homologs) and their effects on actin organization is poorly understood. In this study, we characterized the bundling activity of AtFH8 in vitro and in vivo. Biochemical analysis showed that AtFH8(FH1FH2) could form dimers and bundle preformed actin filaments or induce stellar structures during actin polymerization. Expression of truncated forms of AtFH8 and immunolocalization analysis showed that AtFH8 localized primarily to nuclear envelope in interphase and to the new cell wall after cytokinesis, depending primarily on its N-terminal transmembrane domain. GUS histochemical staining showed AtFH8 was predominantly expressed in Arabidopsis root meristem, vasculature, and outgrowth points of lateral roots. The primary root growth and lateral root initiation of atfh8 could be decreased by latrunculin B (LatB). Analysis of the number of dividing cells in Arabidopsis root tips showed that much fewer dividing cells in Lat B-treated atfh8 plants than wild-type plants, which indicates that AtFH8 was involved in cell division. Actin cytoskeleton in root meristem of atfh8-1 was more sensitive to LatB treatment than that of wild-type. Altogether, our results indicate that AtFH8 is an actin filament nucleator and bundler that functions in cell division and root development.
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Affiliation(s)
- Xiu-Hua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
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Kanneganti V, Gupta AK. RNAi mediated silencing of a wall associated kinase, OsiWAK1 in Oryza sativa results in impaired root development and sterility due to anther indehiscence: Wall Associated Kinases from Oryza sativa. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2011; 17:65-77. [PMID: 23572996 PMCID: PMC3550565 DOI: 10.1007/s12298-011-0050-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Wall-Associated Kinase, one of the receptor-like kinase (RLK) gene families in plant, plays important roles in cell expansion, pathogen resistance and heavy metal stress tolerance in Arabidopsis thaliana. Here, we isolated a cDNA encoding a novel WAK from indica rice and designated as OsiWAK1 (Oryza sativa indica WAK-1). In this study, the RNAi construct with OsiWAK1 gene cloned in sense and antisense orientation separated by a functional intron under constitutive promoter, was introduced through biolistic gene gun method into the rice cultivar "IR-50" to determine the effect of OsiWAK1 transcript silencing on rice plant development. Examination of the transgenic plants reveals that OsiWAK1 transcript silencing in rice results in dwarf plants because of the reduction in the size of leaves, flag-leaves, internodes and panicle. The development of root primordia during germination, root hairs and lateral rooting was also effected. Microscopic analysis revealed that the decrease in size is due to reduction in the cell size but not the number of cells. In addition, the transgenic plants also exhibited sterile phenotype due to anther indehiscence and 40 % reduction in pollen viability. These data suggest that OsiWAK1 may play an important role in rice plant growth and development.
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Affiliation(s)
- Vydehi Kanneganti
- />Department of Plant Biotechnology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021 TamilNadu India
- />Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Aditya Kumar Gupta
- />Department of Plant Biotechnology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021 TamilNadu India
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