1
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Kong SG, Yamazaki Y, Shimada A, Kijima ST, Hirose K, Katoh K, Ahn J, Song HG, Han JW, Higa T, Takano A, Nakamura Y, Suetsugu N, Kohda D, Uyeda TQP, Wada M. CHLOROPLAST UNUSUAL POSITIONING 1 is a plant-specific actin polymerization factor regulating chloroplast movement. THE PLANT CELL 2024; 36:1159-1181. [PMID: 38134410 PMCID: PMC10980345 DOI: 10.1093/plcell/koad320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 11/09/2023] [Accepted: 12/18/2023] [Indexed: 12/24/2023]
Abstract
Plants have unique responses to fluctuating light conditions. One such response involves chloroplast photorelocation movement, which optimizes photosynthesis under weak light by the accumulation of chloroplasts along the periclinal side of the cell, which prevents photodamage under strong light by avoiding chloroplast positioning toward the anticlinal side of the cell. This light-responsive chloroplast movement relies on the reorganization of chloroplast actin (cp-actin) filaments. Previous studies have suggested that CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1) is essential for chloroplast photorelocation movement as a regulator of cp-actin filaments. In this study, we conducted comprehensive analyses to understand CHUP1 function. Functional, fluorescently tagged CHUP1 colocalized with and was coordinately reorganized with cp-actin filaments on the chloroplast outer envelope during chloroplast movement in Arabidopsis thaliana. CHUP1 distribution was reversibly regulated in a blue light- and phototropin-dependent manner. X-ray crystallography revealed that the CHUP1-C-terminal domain shares structural homology with the formin homology 2 (FH2) domain, despite lacking sequence similarity. Furthermore, the CHUP1-C-terminal domain promoted actin polymerization in the presence of profilin in vitro. Taken together, our findings indicate that CHUP1 is a plant-specific actin polymerization factor that has convergently evolved to assemble cp-actin filaments and enables chloroplast photorelocation movement.
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Affiliation(s)
- Sam-Geun Kong
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Yosuke Yamazaki
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Atsushi Shimada
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Saku T Kijima
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Keiko Hirose
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Jeongsu Ahn
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Hyun-Geun Song
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Jae-Woo Han
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Takeshi Higa
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Akira Takano
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Yuki Nakamura
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Noriyuki Suetsugu
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Daisuke Kohda
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Taro Q P Uyeda
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Masamitsu Wada
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
- Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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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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Xie Z, Zhang L, Zhang Q, Lu Y, Dong C, Li D, Liu X, Xia C, Kong X. A Glu209Lys substitution in DRG1/TaACT7, which disturbs F-actin organization, reduces plant height and grain length in bread wheat. THE NEW PHYTOLOGIST 2023; 240:1913-1929. [PMID: 37668262 DOI: 10.1111/nph.19246] [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: 03/13/2023] [Accepted: 08/14/2023] [Indexed: 09/06/2023]
Abstract
Plant height and grain size are two important agronomic traits that are closely related to crop yield. Numerous dwarf and grain-shape mutants have been studied to identify genes that can be used to increase crop yield and improve breeding programs. In this study, we characterized a dominant mutant, dwarf and round grain 1 (drg1-D), in bread wheat (Triticum aestivum L.). drg1-D plants exhibit multiple phenotypic changes, including dwarfism, round grains, and insensitivity to brassinosteroids (BR). Cell structure observation in drg1-D mutant plants showed that the reduced organ size is due to irregular cell shape. Using map-based cloning and verification in transgenic plants, we found that a Glu209Lys substitution in the DRG1 protein is responsible for the irregular cell size and arrangement in the drg1-D mutant. DRG1/TaACT7 encodes an actin family protein that is essential for polymerization stability and microfilament (MF) formation. In addition, the BR response and vesicular transport were altered by the abnormal actin cytoskeleton in drg1-D mutant plants. Our study demonstrates that DRG1/TaACT7 plays an important role in wheat cell shape determination by modulating actin organization and intracellular material transport, which could in the longer term provide tools to better understand the polymerization of actin and its assembly into filaments and arrays.
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Affiliation(s)
- Zhencheng Xie
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Lichao Zhang
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Qiang Zhang
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Yan Lu
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Chunhao Dong
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Danping Li
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xu Liu
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Chuan Xia
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xiuying Kong
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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4
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Cui X, Zou M, Li J. Basally distributed actin array drives embryonic hypocotyl elongation during the seed-to-seedling transition in Arabidopsis. THE NEW PHYTOLOGIST 2023; 240:191-206. [PMID: 37537721 DOI: 10.1111/nph.19149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023]
Abstract
Seed germination is a vital developmental transition for the production of progeny by sexual reproduction in spermatophytes. The seed-to-seedling transition is predominately driven by hypocotyl cell elongation. However, the mechanism that underlies hypocotyl growth remains largely unknown. In this study, we characterized the actin array reorganization in embryonic hypocotyl epidermal cells. Live-cell imaging revealed a basally organized actin array formed during hypocotyl cell elongation. This polarized actin assembly is a barrel-shaped network, which comprises a backbone of longitudinally aligned actin cables and a fine actin cap linking these cables. We provide genetic evidence that the basal actin array formation requires formin-mediated actin polymerization and directional movement of actin filaments powered by myosin XIs. In fh1-1 and xi3ko mutants, actin filaments failed to reorganize into the basal actin array, and the hypocotyl cell elongation was inhibited compared with wild-type plants. Collectively, our work uncovers the molecular mechanisms for basal actin array assembly and demonstrates the connection between actin polarization and hypocotyl elongation during seed-to-seedling transition.
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Affiliation(s)
- Xuan Cui
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Minxia Zou
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Jiejie Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Science, Beijing Normal University, Beijing, 100875, China
- Key Laboratory of Cell Proliferation and Regulation of Ministry of Education, College of Life Science, Beijing Normal University, Beijing, 100875, China
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5
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Stephan OOH. Effects of environmental stress factors on the actin cytoskeleton of fungi and plants: Ionizing radiation and ROS. Cytoskeleton (Hoboken) 2023; 80:330-355. [PMID: 37066976 DOI: 10.1002/cm.21758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/20/2023] [Accepted: 03/29/2023] [Indexed: 04/18/2023]
Abstract
Actin is an abundant and multifaceted protein in eukaryotic cells that has been detected in the cytoplasm as well as in the nucleus. In cooperation with numerous interacting accessory-proteins, monomeric actin (G-actin) polymerizes into microfilaments (F-actin) which constitute ubiquitous subcellular higher order structures. Considering the extensive spatial dimensions and multifunctionality of actin superarrays, the present study analyses the issue if and to what extent environmental stress factors, specifically ionizing radiation (IR) and reactive oxygen species (ROS), affect the cellular actin-entity. In that context, this review particularly surveys IR-response of fungi and plants. It examines in detail which actin-related cellular constituents and molecular pathways are influenced by IR and related ROS. This comprehensive survey concludes that the general integrity of the total cellular actin cytoskeleton is a requirement for IR-tolerance. Actin's functions in genome organization and nuclear events like chromatin remodeling, DNA-repair, and transcription play a key role. Beyond that, it is highly significant that the macromolecular cytoplasmic and cortical actin-frameworks are affected by IR as well. In response to IR, actin-filament bundling proteins (fimbrins) are required to stabilize cables or patches. In addition, the actin-associated factors mediating cellular polarity are essential for IR-survivability. Moreover, it is concluded that a cellular homeostasis system comprising ROS, ROS-scavengers, NADPH-oxidases, and the actin cytoskeleton plays an essential role here. Consequently, besides the actin-fraction which controls crucial genome-integrity, also the portion which facilitates orderly cellular transport and polarized growth has to be maintained in order to survive IR.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria, 91058, Germany
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6
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Collier S, Pietsch E, Dans M, Ling D, Tavella TA, Lopaticki S, Marapana DS, Shibu MA, Andrew D, Tiash S, McMillan PJ, Gilson P, Tilley L, Dixon MWA. Plasmodium falciparum formins are essential for invasion and sexual stage development. Commun Biol 2023; 6:861. [PMID: 37596377 PMCID: PMC10439200 DOI: 10.1038/s42003-023-05233-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 08/09/2023] [Indexed: 08/20/2023] Open
Abstract
The malaria parasite uses actin-based mechanisms throughout its lifecycle to control a range of biological processes including intracellular trafficking, gene regulation, parasite motility and invasion. In this work we assign functions to the Plasmodium falciparum formins 1 and 2 (FRM1 and FRM2) proteins in asexual and sexual blood stage development. We show that FRM1 is essential for merozoite invasion and FRM2 is required for efficient cell division. We also observed divergent functions for FRM1 and FRM2 in gametocyte development. Conditional deletion of FRM1 leads to a delay in gametocyte stage progression. We show that FRM2 controls the actin and microtubule cytoskeletons in developing gametocytes, with premature removal of the protein resulting in a loss of transmissible stage V gametocytes. Lastly, we show that targeting formin proteins with the small molecule inhibitor of formin homology domain 2 (SMIFH2) leads to a multistage block in asexual and sexual stage parasite development.
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Affiliation(s)
- Sophie Collier
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Emma Pietsch
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Madeline Dans
- The Macfarlane Burnet Institute for Medical Research, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Dawson Ling
- The Macfarlane Burnet Institute for Medical Research, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Tatyana A Tavella
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sash Lopaticki
- Department of Infectious Diseases, Doherty Institute, University of Melbourne, Parkville, VIC, 3010, Australia
- Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC, 3052, Australia
| | - Danushka S Marapana
- Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC, 3052, Australia
| | - Mohini A Shibu
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Dean Andrew
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Snigdha Tiash
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Paul J McMillan
- Biological Optical Microscopy Platform, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Paul Gilson
- The Macfarlane Burnet Institute for Medical Research, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Matthew W A Dixon
- Department of Infectious Diseases, Doherty Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
- Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC, 3052, Australia.
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Zhang Y, Dong G, Wu L, Wang X, Chen F, Xiong E, Xiong G, Zhou Y, Kong Z, Fu Y, Zeng D, Ma D, Qian Q, Yu Y. Formin protein DRT1 affects gross morphology and chloroplast relocation in rice. PLANT PHYSIOLOGY 2023; 191:280-298. [PMID: 36102807 PMCID: PMC9806613 DOI: 10.1093/plphys/kiac427] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
Plant height and tiller number are two major factors determining plant architecture and yield. However, in rice (Oryza sativa), the regulatory mechanism of plant architecture remains to be elucidated. Here, we reported a recessive rice mutant presenting dwarf and reduced tillering phenotypes (drt1). Map-based cloning revealed that the phenotypes are caused by a single point mutation in DRT1, which encodes the Class I formin protein O. sativa formin homolog 13 (OsFH13), binds with F-actin, and promotes actin polymerization for microfilament organization. DRT1 protein localized on the plasma membrane (PM) and chloroplast (CP) outer envelope. DRT1 interacted with rice phototropin 2 (OsPHOT2), and the interaction was interrupted in drt1. Upon blue light stimulus, PM localized DRT1 and OsPHOT2 were translocated onto the CP membrane. Moreover, deficiency of DRT1 reduced OsPHOT2 internalization and OsPHOT2-mediated CP relocation. Our study suggests that rice formin protein DRT1/OsFH13 is necessary for plant morphology and CP relocation by modulating the actin-associated cytoskeleton network.
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Affiliation(s)
- Yanli Zhang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China
| | - Guojun Dong
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Limin Wu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Xuewen Wang
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Athens, Georgia, 30601, USA
| | - Fei Chen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Erhui Xiong
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Guosheng Xiong
- Institute of Agricultural Genomics, Chinese Academy of Agricultural Sciences, Shenzhen, 100018, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Dali Zeng
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Dianrong Ma
- Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China
| | - Qian Qian
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Yanchun Yu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou Normal University, Hangzhou, 310036, China
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8
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Muresan CG, Sun ZG, Yadav V, Tabatabai AP, Lanier L, Kim JH, Kim T, Murrell MP. F-actin architecture determines constraints on myosin thick filament motion. Nat Commun 2022; 13:7008. [PMID: 36385016 PMCID: PMC9669029 DOI: 10.1038/s41467-022-34715-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 11/03/2022] [Indexed: 11/17/2022] Open
Abstract
Active stresses are generated and transmitted throughout diverse F-actin architectures within the cell cytoskeleton, and drive essential behaviors of the cell, from cell division to migration. However, while the impact of F-actin architecture on the transmission of stress is well studied, the role of architecture on the ab initio generation of stresses remains less understood. Here, we assemble F-actin networks in vitro, whose architectures are varied from branched to bundled through F-actin nucleation via Arp2/3 and the formin mDia1. Within these architectures, we track the motions of embedded myosin thick filaments and connect them to the extent of F-actin network deformation. While mDia1-nucleated networks facilitate the accumulation of stress and drive contractility through enhanced actomyosin sliding, branched networks prevent stress accumulation through the inhibited processivity of thick filaments. The reduction in processivity is due to a decrease in translational and rotational motions constrained by the local density and geometry of F-actin.
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Affiliation(s)
- Camelia G Muresan
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - Zachary Gao Sun
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA
| | - Vikrant Yadav
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - A Pasha Tabatabai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - Laura Lanier
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - June Hyung Kim
- Weldon School of Biomedical Engineering, Purdue University, 206S. Martin Jischke Drive, West Lafayette, IN, 47907, USA
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, 206S. Martin Jischke Drive, West Lafayette, IN, 47907, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA.
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA.
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9
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Silva AM, Chan FY, Norman MJ, Sobral AF, Zanin E, Gassmann R, Belmonte JM, Carvalho AX. β-heavy-spectrin stabilizes the constricting contractile ring during cytokinesis. J Cell Biol 2022; 222:213538. [PMID: 36219157 PMCID: PMC9559602 DOI: 10.1083/jcb.202202024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/22/2022] Open
Abstract
Cytokinesis requires the constriction of an actomyosin-based contractile ring and involves multiple F-actin crosslinkers. We show that partial depletion of the C. elegans cytokinetic formin generates contractile rings with low F-actin levels that constrict but are structurally fragile, and we use this background to investigate the roles of the crosslinkers plastin/PLST-1 and β-heavy-spectrin/SMA-1 during ring constriction. We show that the removal of PLST-1 or SMA-1 has opposite effects on the structural integrity of fragile rings. PLST-1 loss reduces cortical tension that resists ring constriction and makes fragile rings less prone to ruptures and regressions, whereas SMA-1 loss exacerbates structural defects, leading to frequent ruptures and cytokinesis failure. Fragile rings without SMA-1 or containing a shorter SMA-1, repeatedly rupture at the same site, and SMA-1::GFP accumulates at repair sites in fragile rings and in rings cut by laser microsurgery. These results establish that β-heavy-spectrin stabilizes the constricting ring and reveals the importance of β-heavy-spectrin size for network connectivity at low F-actin density.
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Affiliation(s)
- Ana Marta Silva
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Michael J. Norman
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Filipa Sobral
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Esther Zanin
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Reto Gassmann
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Julio Monti Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Xavier Carvalho
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal,Correspondence to Ana Xavier Carvalho:
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10
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Ren A, Zhang J, Liu Z, Du P, Zhang F, Ren H, Zhang D. OsFH13, a type I formin, is indispensable for rice morphogenesis. REPRODUCTION AND BREEDING 2022. [DOI: 10.1016/j.repbre.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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11
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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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12
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Shevchenko GV, Krutovsky KV. Mechanical stress effects on transcriptional regulation of genes encoding microtubule- and actin-associated proteins. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2022; 28:17-30. [PMID: 35210715 PMCID: PMC8847523 DOI: 10.1007/s12298-021-01123-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
Plant cytoskeleton regulation has been studied using a new approach based on both (1) pharmacological analysis of tubulin and actin inhibitors and (2) mechanical stimulation achieved by using a slow-rotating (2 rpm) clinostat in combination with transcriptional analysis of genes encoding TUA6, ACT2, MAP65-1, CLASP, PLDδ, FH4 and FH1 proteins in Arabidopsis thaliana seedling roots. The obtained data suggest feedback between the organization of microtubule (MT) and actin filament (AF) networks and the expression of the ACT2, TUA6, MAP65-1, CLASP and FH1/FH4 genes. Different regulation of feedback between MT/AF organization and TUA6, ACT2, MAP65-1, CLASP, FH4 and FH1 gene expression was noted during slow clinorotation, possibly due to altered mechanical impact on the cortical cytoskeleton. For the first time, the expression of the tubulin-associated gene MAP65-1 was shown to be dependent upon the organization of AFs. TUA6, MAP65-1, CLASP, FH1 and FH4 likely participate in mechanical signal transduction. Our work demonstrated that slow clinorotation is able to cause mechanical stress.
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Affiliation(s)
- Galina V. Shevchenko
- Institute of Botany, National Academy of Sciences of Ukraine, Kiev, 01004 Ukraine
| | - Konstantin V. Krutovsky
- Department of Forest Genetics and Forest Tree Breeding, Georg-August University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
- Center for Integrated Breeding Research, Georg-August University of Göttingen, 37075 Göttingen, Germany
- Laboratory of Population Genetics, N.I. Vavilov Institute of General Genetics, Russian Academy of Sciences, 119333 Moscow, Russian Federation
- Department of Genomics and Bioinformatics, Laboratory of Forest Genomics, Genome Research and Education Center, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 660036 Krasnoyarsk, Russian Federation
- Scientific and Methodological Center, G. F. Morozov Voronezh State University of Forestry and Technologies, 394087 Voronezh, Russian Federation
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13
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Martinière A, Zelazny E. Membrane nanodomains and transport functions in plant. PLANT PHYSIOLOGY 2021; 187:1839-1855. [PMID: 35235669 PMCID: PMC8644385 DOI: 10.1093/plphys/kiab312] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/16/2021] [Indexed: 05/25/2023]
Abstract
Far from a homogeneous environment, biological membranes are highly structured with lipids and proteins segregating in domains of different sizes and dwell times. In addition, membranes are highly dynamics especially in response to environmental stimuli. Understanding the impact of the nanoscale organization of membranes on cellular functions is an outstanding question. Plant channels and transporters are tightly regulated to ensure proper cell nutrition and signaling. Increasing evidence indicates that channel and transporter nano-organization within membranes plays an important role in these regulation mechanisms. Here, we review recent advances in the field of ion, water, but also hormone transport in plants, focusing on protein organization within plasma membrane nanodomains and its cellular and physiological impacts.
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Affiliation(s)
| | - Enric Zelazny
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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14
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Sun H, Zhu X, Li C, Ma Z, Han X, Luo Y, Yang L, Yu J, Miao Y. Xanthomonas effector XopR hijacks host actin cytoskeleton via complex coacervation. Nat Commun 2021; 12:4064. [PMID: 34210966 PMCID: PMC8249405 DOI: 10.1038/s41467-021-24375-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 06/11/2021] [Indexed: 01/09/2023] Open
Abstract
The intrinsically disordered region (IDR) is a preserved signature of phytobacterial type III effectors (T3Es). The T3E IDR is thought to mediate unfolding during translocation into the host cell and to avoid host defense by sequence diversification. Here, we demonstrate a mechanism of host subversion via the T3E IDR. We report that the Xanthomonas campestris T3E XopR undergoes liquid-liquid phase separation (LLPS) via multivalent IDR-mediated interactions that hijack the Arabidopsis actin cytoskeleton. XopR is gradually translocated into host cells during infection and forms a macromolecular complex with actin-binding proteins at the cell cortex. By tuning the physical-chemical properties of XopR-complex coacervates, XopR progressively manipulates multiple steps of actin assembly, including formin-mediated nucleation, crosslinking of F-actin, and actin depolymerization, which occurs through competition for actin-depolymerizing factor and depends on constituent stoichiometry. Our findings unravel a sophisticated strategy in which bacterial T3E subverts the host actin cytoskeleton via protein complex coacervation.
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Affiliation(s)
- He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xinlu Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Chuanxi Li
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yuanyuan Luo
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jing Yu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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15
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Liu C, Zhang Y, Ren H. Profilin promotes formin-mediated actin filament assembly and vesicle transport during polarity formation in pollen. THE PLANT CELL 2021; 33:1252-1267. [PMID: 33638636 DOI: 10.1093/plcell/koab027] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Pollen germination is critical for the reproduction of flowering plants. Formin-dependent actin polymerization plays vital roles in vesicle trafficking and polarity establishment during this process. However, how formin-mediated actin assembly is regulated in vivo remains poorly understood. Here, we investigated the function of reproductive profilin 4 and 5 (PRF4 and PRF5) in polarity establishment during pollen germination in Arabidopsis thaliana. Our data showed that the actin filament content was reduced in the prf4 prf5 double mutant and substantially increased in both PRF4- and PRF5-overexpressing pollen grains. By contrast, the positive effect of profilin in promoting actin polymerization was abolished in a formin mutant, atfh5. In addition, the interaction between Arabidopsis formin homology 5 (AtFH5) and actin filaments was attenuated and the trafficking of AtFH5-labeled vesicles was slowed in prf4 prf5 pollen grains. Formation of the collar-like structure at the germination pore was also defective in prf4 prf5 pollen grains as the fast assembly of actin filaments was impaired. Together, our results suggest that PRF4 and PRF5 regulate vesicle trafficking and polarity establishment during pollen germination by promoting AtFH5-mediated actin polymerization and enhancing the interaction between AtFH5 and actin filaments.
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Affiliation(s)
- Chang Liu
- Center for Biological Science and Technology, Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Haiyun Ren
- Center for Biological Science and Technology, Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China
- 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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16
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Hayashi M, Palmgren M. The quest for the central players governing pollen tube growth and guidance. PLANT PHYSIOLOGY 2021; 185:682-693. [PMID: 33793904 PMCID: PMC8133568 DOI: 10.1093/plphys/kiaa092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/06/2020] [Indexed: 05/02/2023]
Abstract
Recent insights into the mechanism of pollen tube growth and guidance point to the importance of H+ dynamics, which are regulated by the plasma membrane H+-ATPase.
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Affiliation(s)
- Maki Hayashi
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000,China
- Author for communication:
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17
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Du P, Wang J, He Y, Zhang S, Hu B, Xue X, Miao L, Ren H. AtFH14 crosslinks actin filaments and microtubules in different manners. Biol Cell 2021; 113:235-249. [PMID: 33386758 DOI: 10.1111/boc.202000147] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND INFORMATION In many cellular processes including cell division, the synergistic dynamics of actin filaments and microtubules play vital roles. However, the regulatory mechanisms of these synergistic dynamics are not fully understood. Proteins such as formins are involved in actin filament-microtubule interactions and Arabidopsis thaliana formin 14 (AtFH14) may function as a crosslinker between actin filaments and microtubules in cell division, but the molecular mechanism underlying such crosslinking remains unclear. RESULTS Without microtubules, formin homology (FH) 1/FH2 of AtFH14 nucleated actin polymerisation from actin monomers and capped the barbed end of actin filaments. However, in the presence of microtubules, quantitative analysis showed that the binding affinity of AtFH14 FH1FH2 to microtubules was higher than that to actin filaments. Moreover, microtubule-bound AtFH14 FH1FH2 neither nucleated actin polymerisation nor inhibited barbed end elongation. In contrast, tubulin did not affect AtFH14 FH1FH2 to nucleate actin polymerisation and inhibit barbed end elongation. Nevertheless, microtubule-bound AtFH14 FH1FH2 bound actin filaments and the bound actin filaments slid and elongated along the microtubules or elongated away from the microtubules, which induced bundling or crosslinking of actin filaments and microtubules. Pharmacological analyses indicated that AtFH14 FH1FH2 promoted crosslinking of actin filaments and microtubules in vivo. Additionally, co-sedimentation and fluorescent dye-labelling experiments of AtFH14 FH2-truncated proteins in vitro revealed the essential motifs of bundling actin filaments or microtubules, which were 63-92 aa and 42-62 aa in the AtFH14 FH2 N-terminal, respectively, and 42-62 aa was the essential motif to crosslink actin filaments and microtubules. CONCLUSIONS AND SIGNIFICANCE Our results aid in explaining how AtFH14 functions as a crosslinker between actin filaments and microtubules to regulate their dynamics via different manners during cell division. They also facilitate further understanding of the molecular mechanisms of the interactions between actin filaments and microtubules.
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Affiliation(s)
- Pingzhou Du
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Jiaojiao Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Yunqiu He
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Bailing Hu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Long Miao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
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18
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García-González J, van Gelderen K. Bundling up the Role of the Actin Cytoskeleton in Primary Root Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:777119. [PMID: 34975959 PMCID: PMC8716943 DOI: 10.3389/fpls.2021.777119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/11/2021] [Indexed: 05/19/2023]
Abstract
Primary root growth is required by the plant to anchor in the soil and reach out for nutrients and water, while dealing with obstacles. Efficient root elongation and bending depends upon the coordinated action of environmental sensing, signal transduction, and growth responses. The actin cytoskeleton is a highly plastic network that constitutes a point of integration for environmental stimuli and hormonal pathways. In this review, we present a detailed compilation highlighting the importance of the actin cytoskeleton during primary root growth and we describe how actin-binding proteins, plant hormones, and actin-disrupting drugs affect root growth and root actin. We also discuss the feedback loop between actin and root responses to light and gravity. Actin affects cell division and elongation through the control of its own organization. We remark upon the importance of longitudinally oriented actin bundles as a hallmark of cell elongation as well as the role of the actin cytoskeleton in protein trafficking and vacuolar reshaping during this process. The actin network is shaped by a plethora of actin-binding proteins; however, there is still a large gap in connecting the molecular function of these proteins with their developmental effects. Here, we summarize their function and known effects on primary root growth with a focus on their high level of specialization. Light and gravity are key factors that help us understand root growth directionality. The response of the root to gravity relies on hormonal, particularly auxin, homeostasis, and the actin cytoskeleton. Actin is necessary for the perception of the gravity stimulus via the repositioning of sedimenting statoliths, but it is also involved in mediating the growth response via the trafficking of auxin transporters and cell elongation. Furthermore, auxin and auxin analogs can affect the composition of the actin network, indicating a potential feedback loop. Light, in its turn, affects actin organization and hence, root growth, although its precise role remains largely unknown. Recently, fundamental studies with the latest techniques have given us more in-depth knowledge of the role and organization of actin in the coordination of root growth; however, there remains a lot to discover, especially in how actin organization helps cell shaping, and therefore root growth.
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Affiliation(s)
- Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Judith García-González,
| | - Kasper van Gelderen
- Plant Ecophysiology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
- Kasper van Gelderen,
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19
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Zweifel ME, Courtemanche N. Competition for delivery of profilin-actin to barbed ends limits the rate of formin-mediated actin filament elongation. J Biol Chem 2020; 295:4513-4525. [PMID: 32075907 DOI: 10.1074/jbc.ra119.012000] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/11/2020] [Indexed: 11/06/2022] Open
Abstract
Formins direct the elongation of unbranched actin filaments by binding their barbed ends and processively stepping onto incoming actin monomers to incorporate them into the filament. Binding of profilin to actin monomers creates profilin-actin complexes, which then bind polyproline tracts located in formin homology 1 (FH1) domains. Diffusion of these natively disordered domains enables direct delivery of profilin-actin to the barbed end, speeding the rate of filament elongation. In this study, we investigated the mechanism of coordinated actin delivery from the multiple polyproline tracts in formin FH1 domains. We found that each polyproline tract can efficiently mediate polymerization, but that all tracts do not generate the same rate of elongation. In WT FH1 domains, the multiple polyproline tracts compete to deliver profilin-actin to the barbed end. This competition ultimately limits the rate of formin-mediated elongation. We propose that intrinsic properties of the filament-binding FH2 domain tune the efficiency of FH1-mediated elongation by directly regulating the rate of monomer incorporation at the barbed end. A strong correlation between competitive FH1-mediated profilin-actin delivery and FH2-regulated gating of the barbed end effectively limits the elongation rate, thereby obviating the need for evolutionary optimization of FH1 domain sequences.
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Affiliation(s)
- Mark E Zweifel
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Naomi Courtemanche
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
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20
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Rui Y, Dinneny JR. A wall with integrity: surveillance and maintenance of the plant cell wall under stress. THE NEW PHYTOLOGIST 2020; 225:1428-1439. [PMID: 31486535 DOI: 10.1111/nph.16166] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/16/2019] [Indexed: 05/21/2023]
Abstract
The structural and functional integrity of the cell wall needs to be constantly monitored and fine-tuned to allow for growth while preventing mechanical failure. Many studies have advanced our understanding of the pathways that contribute to cell wall biosynthesis and how these pathways are regulated by external and internal cues. Recent evidence also supports a model in which certain aspects of the wall itself may act as growth-regulating signals. Molecular components of the signaling pathways that sense and maintain cell wall integrity have begun to be revealed, including signals arising in the wall, sensors that detect changes at the cell surface, and downstream signal transduction modules. Abiotic and biotic stress conditions provide new contexts for the study of cell wall integrity, but the nature and consequences of wall disruptions due to various stressors require further investigation. A deeper understanding of cell wall signaling will provide insights into the growth regulatory mechanisms that allow plants to survive in changing environments.
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Affiliation(s)
- Yue Rui
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305, USA
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA
| | - José R Dinneny
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305, USA
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA
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21
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Oulehlová D, Kollárová E, Cifrová P, Pejchar P, Žárský V, Cvrčková F. Arabidopsis Class I Formin FH1 Relocates between Membrane Compartments during Root Cell Ontogeny and Associates with Plasmodesmata. PLANT & CELL PHYSIOLOGY 2019; 60:1855-1870. [PMID: 31135031 DOI: 10.1093/pcp/pcz102] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 05/14/2019] [Indexed: 05/03/2023]
Abstract
Formins are evolutionarily conserved eukaryotic proteins engaged in actin nucleation and other aspects of cytoskeletal organization. Angiosperms have two formin clades with multiple paralogs; typical plant Class I formins are integral membrane proteins that can anchor cytoskeletal structures to membranes. For the main Arabidopsis housekeeping Class I formin, FH1 (At3g25500), plasmalemma localization was documented in heterologous expression and overexpression studies. We previously showed that loss of FH1 function increases cotyledon epidermal pavement cell shape complexity via modification of actin and microtubule organization and dynamics. Here, we employ transgenic Arabidopsis expressing green fluorescent protein-tagged FH1 (FH1-GFP) from its native promoter to investigate in vivo behavior of this formin using advanced microscopy techniques. The fusion protein is functional, since its expression complements the fh1 loss-of-function mutant phenotype. Accidental overexpression of FH1-GFP results in a decrease in trichome branch number, while fh1 mutation has the opposite effect, indicating a general role of this formin in controlling cell shape complexity. Consistent with previous reports, FH1-GFP associates with membranes. However, the protein exhibits surprising actin- and secretory pathway-dependent dynamic localization and relocates between cellular endomembranes and the plasmalemma during cell division and differentiation in root tissues, with transient tonoplast localization at the transition/elongation zones border. FH1-GFP also accumulates in actin-rich regions of cortical cytoplasm and associates with plasmodesmata in both the cotyledon epidermis and root tissues. Together with previous reports from metazoan systems, this suggests that formins might have a shared (ancestral or convergent) role at cell-cell junctions.
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Affiliation(s)
- Denisa Oulehlová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
- Institute of Experimental Botany of the CAS, Prague 6, CZ 165 02, Czech Republic
| | - Eva Kollárová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
| | - Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
| | - Přemysl Pejchar
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
- Institute of Experimental Botany of the CAS, Prague 6, CZ 165 02, Czech Republic
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
- Institute of Experimental Botany of the CAS, Prague 6, CZ 165 02, Czech Republic
| | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, CZ 128 43, Czech Republic
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22
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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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23
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Liu C, Zhang Y, Ren H. Actin Polymerization Mediated by AtFH5 Directs the Polarity Establishment and Vesicle Trafficking for Pollen Germination in Arabidopsis. MOLECULAR PLANT 2018; 11:1389-1399. [PMID: 30296598 DOI: 10.1016/j.molp.2018.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/10/2018] [Accepted: 09/27/2018] [Indexed: 05/13/2023]
Abstract
The process of pollen germination is crucial for flowering plant reproduction, but the mechanisms through which pollen grains establish polarity and select germination sites are not well understood. In this study, we report that a formin family protein, AtFH5, is localized to the vesicles and rotates ahead of Lifeact-mEGFP-labeled actin filaments during pollen germination. The translocation of AtFH5 to the plasma membrane initiates the assembly of a collar-like actin structure at the prospective germination site prior to germination. Genetic and pharmacological evidence further revealed an interdependent relationship between the mobility of AtFH5-labeled vesicles and the polymerization of actin filaments: vesicle-localized AtFH5 promotes actin assembly, and the polymerization and elongation of actin filaments, in turn, is essential for the mobility of AtFH5-labeled vesicles in pollen grains. Taken together, our work revealed a molecular mechanism underlying the polarity establishment and vesicle mobility during pollen germination.
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Affiliation(s)
- Chang Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Haiyun Ren
- 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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24
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Courtemanche N. Mechanisms of formin-mediated actin assembly and dynamics. Biophys Rev 2018; 10:1553-1569. [PMID: 30392063 DOI: 10.1007/s12551-018-0468-6] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/18/2018] [Indexed: 12/14/2022] Open
Abstract
Cellular viability requires tight regulation of actin cytoskeletal dynamics. Distinct families of nucleation-promoting factors enable the rapid assembly of filament nuclei that elongate and are incorporated into diverse and specialized actin-based structures. In addition to promoting filament nucleation, the formin family of proteins directs the elongation of unbranched actin filaments. Processive association of formins with growing filament ends is achieved through continuous barbed end binding of the highly conserved, dimeric formin homology (FH) 2 domain. In cooperation with the FH1 domain and C-terminal tail region, FH2 dimers mediate actin subunit addition at speeds that can dramatically exceed the rate of spontaneous assembly. Here, I review recent biophysical, structural, and computational studies that have provided insight into the mechanisms of formin-mediated actin assembly and dynamics.
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Affiliation(s)
- Naomi Courtemanche
- Department of Genetics, Cell and Developmental Biology, University of Minnesota, 420 Washington Ave SE, 6-130 MCB, Minneapolis, MN, 55455, USA.
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25
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Li J, Chen S, Wang X, Shi C, Liu H, Yang J, Shi W, Guo J, Jia H. Hydrogen Sulfide Disturbs Actin Polymerization via S-Sulfhydration Resulting in Stunted Root Hair Growth. PLANT PHYSIOLOGY 2018; 178:936-949. [PMID: 30166418 PMCID: PMC6181039 DOI: 10.1104/pp.18.00838] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/21/2018] [Indexed: 05/20/2023]
Abstract
Hydrogen sulfide (H2S) is an important signaling molecule in plants. Our previous report suggested that H2S signaling affects the actin cytoskeleton and root hair growth. However, the underlying mechanisms of its effects are not understood. S-Sulfhydration of proteins is regulated directly by H2S, which converts the thiol groups of cysteine (Cys) residues to persulfides and alters protein function. In this work, we studied the effects of S-sulfhydration on actin dynamics in Arabidopsis (Arabidopsis thaliana). We generated transgenic plants overexpressing the H2S biosynthesis-related genes l-CYSTEINE DESULFHYDRASE (LCD) and d-CYSTEINE DESULFHYDRASE in the O-acetylserine(thiol)lyase isoform a1 (oasa1) mutant and Columbia-0 backgrounds. The H2S content increased significantly in overexpressing LCD/oasa1 plants. The density of filamentous actin (F-actin) bundles and the F-actin/globular actin ratio decreased in overexpressing LCD/oasa1 plants. S-Sulfhydration also was enhanced in overexpressing LCD/oasa1 plants. An analysis of actin dynamics suggested that S-sulfhydration inhibited actin polymerization. We also found that ACTIN2 (ACT2) was S-sulfhydrated at Cys-287. Cys-287 is adjacent to the D-loop, which acts as a central region for hydrophobic and electrostatic interactions and stabilizes F-actin filaments. Overaccumulation of H2S caused the depolymerization of F-actin bundles and inhibited root hair growth. Introduction of ACT2 carrying a Cys-287-to-Ser mutation into an act2-1 mutant partially suppressed H2S-dependent inhibition of root hair growth. We conclude that H2S regulates actin dynamics and affects root hair growth.
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Affiliation(s)
- Jisheng Li
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
- Biomass Energy Center for Arid and Semi-arid Lands, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Sisi Chen
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaofeng Wang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Cong Shi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Huaxin Liu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Jun Yang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Wei Shi
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Junkang Guo
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
| | - Honglei Jia
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China
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26
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Sherer LA, Zweifel ME, Courtemanche N. Dissection of two parallel pathways for formin-mediated actin filament elongation. J Biol Chem 2018; 293:17917-17928. [PMID: 30266808 DOI: 10.1074/jbc.ra118.004845] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/25/2018] [Indexed: 11/06/2022] Open
Abstract
Formins direct the elongation of unbranched actin filaments that are incorporated into a diverse set of cytoskeletal structures. Elongation of formin-bound filaments occurs along two parallel pathways. The formin homology 2 (FH2) pathway allows actin monomers to bind directly to barbed ends bound by dimeric FH2 domains. The formin homology 1 (FH1) pathway involves transfer of profilin-bound actin to the barbed end from polyproline tracts located in the disordered FH1 domains. Here, we used a total internal reflection fluorescence (TIRF) microscopy-based fluorescence approach to determine the fraction of actin subunits incorporated via the FH1 and FH2 pathways during filament elongation mediated by two formins. We found that the fraction of filament elongation that occurs via each pathway directly depends on the efficiency of the other pathway, indicating that these two pathways compete with each other for subunit addition by formins. We conclude that this competition allows formins to compensate for changes in the efficiency of one pathway by adjusting the frequency of subunit addition via the other, thus increasing the overall robustness of formin-mediated actin polymerization.
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Affiliation(s)
- Laura A Sherer
- From the Department of Genetics, Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Mark E Zweifel
- From the Department of Genetics, Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota 55455
| | - Naomi Courtemanche
- From the Department of Genetics, Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota 55455.
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27
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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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28
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Sun H, Qiao Z, Chua KP, Tursic A, Liu X, Gao YG, Mu Y, Hou X, Miao Y. Profilin Negatively Regulates Formin-Mediated Actin Assembly to Modulate PAMP-Triggered Plant Immunity. Curr Biol 2018; 28:1882-1895.e7. [PMID: 29861135 DOI: 10.1016/j.cub.2018.04.045] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 03/01/2018] [Accepted: 04/13/2018] [Indexed: 11/26/2022]
Abstract
Profilin functions with formin in actin assembly, a process that regulates multiple aspects of plant development and immune responses. High-level eukaryotes contain multiple isoforms of profilin, formin, and actin, whose partner-specific interactions in actin assembly are not completely understood in plant development and defense responses. To examine the functionally distinct interactions between profilin and formin, we studied all five Arabidopsis profilins and their interactions with formin by using both in vitro biochemical and in vivo cell biology approaches. Unexpectedly, we found a previously undescribed negative regulatory function of AtPRF3 in AtFH1-mediated actin polymerization. The N-terminal 37 residues of AtPRF3 were identified to play a predominant role in inhibiting formin-mediated actin nucleation via their high affinity for the formin polyproline region and their triggering of the oligomerization of AtPRF3. Both in vivo and in vitro mechanistic studies of AtPRF3 revealed a universal mechanism in which the weak interaction between profilin and formin positively regulates actin assembly by ensuring rapid recycling of profilin, whereas profilin oligomerization negatively regulates actin polymerization. Upon recognition of the pathogen-associated molecular pattern, the gene transcription and protein degradation of AtPRF3 are modulated for actin assembly during plant innate immunity. The prf3 Arabidopsis plants show higher sensitivity to the bacterial flagellum peptide in both the plant growth and ROS responses. These findings demonstrate a profilin-mediated actin assembly mechanism underlying the plant immune responses.
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Affiliation(s)
- He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Zhu Qiao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Khi Pin Chua
- Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637371, Singapore
| | - Alma Tursic
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xu Liu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yong-Gui Gao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Institute of Molecular and Cell Biology, A(∗)STAR, Singapore 138673, Singapore
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xingliang Hou
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
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29
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Paez-Garcia A, Sparks JA, de Bang L, Blancaflor EB. Plant Actin Cytoskeleton: New Functions from Old Scaffold. PLANT CELL MONOGRAPHS 2018. [DOI: 10.1007/978-3-319-69944-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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30
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Szymanski D, Staiger CJ. The Actin Cytoskeleton: Functional Arrays for Cytoplasmic Organization and Cell Shape Control. PLANT PHYSIOLOGY 2018; 176:106-118. [PMID: 29192029 PMCID: PMC5761824 DOI: 10.1104/pp.17.01519] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/29/2017] [Indexed: 05/18/2023]
Abstract
Functionally distinct actin filament arrays cluster organelles and define cellular scale flow patterns for secretion.
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Affiliation(s)
- Dan Szymanski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
- Department of Agronomy, Purdue University, West Lafayette, Indiana 47907
| | - Christopher J Staiger
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
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31
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Silkworth WT, Kunes KL, Nickel GC, Phillips ML, Quinlan ME, Vizcarra CL. The neuron-specific formin Delphilin nucleates nonmuscle actin but does not enhance elongation. Mol Biol Cell 2017; 29:610-621. [PMID: 29282276 PMCID: PMC6004577 DOI: 10.1091/mbc.e17-06-0363] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/06/2017] [Accepted: 12/22/2017] [Indexed: 12/11/2022] Open
Abstract
The formin Delphilin binds the glutamate receptor, GluRδ2, in dendritic spines of Purkinje cells. Both proteins play a role in learning. To understand how Delphilin functions in neurons, we studied the actin assembly properties of this formin. Formins have a conserved formin homology 2 domain, which nucleates and associates with the fast-growing end of actin filaments, influencing filament growth together with the formin homology 1 (FH1) domain. The strength of nucleation and elongation varies widely across formins. Additionally, most formins have conserved domains that regulate actin assembly through an intramolecular interaction. Delphilin is distinct from other formins in several ways: its expression is limited to Purkinje cells, it lacks classical autoinhibitory domains, and its FH1 domain has minimal proline-rich sequence. We found that Delphilin is an actin nucleator that does not accelerate elongation, although it binds to the barbed end of filaments. In addition, Delphilin exhibits a preference for actin isoforms, nucleating nonmuscle actin but not muscle actin, which has not been described or systematically studied in other formins. Finally, Delphilin is the first formin studied that is not regulated by intramolecular interactions. We speculate how the activity we observe is consistent with its localization in the small dendritic spines.
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Affiliation(s)
- William T Silkworth
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Kristina L Kunes
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Grace C Nickel
- Department of Chemistry, Barnard College, New York, NY 10027
| | - Martin L Phillips
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Margot E Quinlan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095 .,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
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32
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Patel AA, Oztug Durer ZA, van Loon AP, Bremer KV, Quinlan ME. Drosophila and human FHOD family formin proteins nucleate actin filaments. J Biol Chem 2017; 293:532-540. [PMID: 29127202 DOI: 10.1074/jbc.m117.800888] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/26/2017] [Indexed: 01/09/2023] Open
Abstract
Formins are a conserved group of proteins that nucleate and processively elongate actin filaments. Among them, the formin homology domain-containing protein (FHOD) family of formins contributes to contractility of striated muscle and cell motility in several contexts. However, the mechanisms by which they carry out these functions remain poorly understood. Mammalian FHOD proteins were reported not to accelerate actin assembly in vitro; instead, they were proposed to act as barbed end cappers or filament bundlers. Here, we show that purified Drosophila Fhod and human FHOD1 both accelerate actin assembly by nucleation. The nucleation activity of FHOD1 is restricted to cytoplasmic actin, whereas Drosophila Fhod potently nucleates both cytoplasmic and sarcomeric actin isoforms. Drosophila Fhod binds tightly to barbed ends, where it slows elongation in the absence of profilin and allows, but does not accelerate, elongation in the presence of profilin. Fhod antagonizes capping protein but dissociates from barbed ends relatively quickly. Finally, we determined that Fhod binds the sides of and bundles actin filaments. This work establishes that Fhod shares the capacity of other formins to nucleate and bundle actin filaments but is notably less effective at processively elongating barbed ends than most well studied formins.
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Affiliation(s)
- Aanand A Patel
- From the Molecular Biology Interdepartmental Doctoral Program
| | | | | | | | - Margot E Quinlan
- the Department of Chemistry and Biochemistry, and .,the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California 90095
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33
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Tan JJD, Ma Z, Xie Y, Yang L, Miao Y. Quantitative analysis of actin filament assembly in yeast and plant by live cell fluorescence microscopy. Micron 2017; 103:78-83. [PMID: 28992458 DOI: 10.1016/j.micron.2017.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/25/2017] [Accepted: 09/25/2017] [Indexed: 10/18/2022]
Abstract
Eukaryotic cells depend on a dynamic actin cytoskeleton to regulate many conserved intracellular events such as endocytosis, morphogenesis, polarized cell growth, and cytokinesis (Engqvist-Goldstein and Drubin, 2003; Salbreux et al., 2012; Pruyne et al., 2004; Pollard, 2010). These activities depend on a precise and well-organized spatiotemporal actin assembly that involves many conserved processes found in eukaryotic cells ranging from a unicellular organism, such as yeast, to multicellular organisms, such as plants and human. In particular, both budding yeast Saccharomyces cerevisiae and plant Arabidopsis thaliana have been proven to be the powerful and great model organisms to study the molecular mechanisms of the polymerization of the actin cytoskeleton and the actin-driven processes in walled-cells. Here we describe the methods in imaging and image processing to analyze dynamic actin filament assembly in budding yeast and Arabidopsis using a wide-field fluorescent microscope.
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Affiliation(s)
- Joseph Jun Dao Tan
- Ageing Research Institute for Society and Education, Interdisciplinary Graduate School, Nanyang Technological University, 639798, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Ying Xie
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 637459, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, 637459, Singapore.
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34
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Sun T, Li S, Ren H. OsFH15, a class I formin, interacts with microfilaments and microtubules to regulate grain size via affecting cell expansion in rice. Sci Rep 2017; 7:6538. [PMID: 28747699 PMCID: PMC5529588 DOI: 10.1038/s41598-017-06431-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 06/13/2017] [Indexed: 11/23/2022] Open
Abstract
Grain size is an important agronomic trait determining rice yield and is mainly restricted by spikelet hull size. However, it remains largely unknown how the spikelet hull size is regulated. In this study, OsFH15, a class I formin protein in Oryza sativa, was found to be able to regulate the size of cells and spikelet hull. OsFH15-Cas9 and OsFH15-RNAi mutants had decreased grain size with reduced cell length, cell width and cell area of inner epidermal cells of the lemma compared with wild-type plants. By contrast, OsFH15-overexpressed plants had increased grain size with larger cells, as well as more abundant microtubules (MTs) and actin filaments (AFs) arrays. OsFH15 was mainly expressed in shoot apical meristem (SAM), spikelets, spikelet hulls and seeds in rice. In vitro biochemical experiments showed that OsFH15 can efficiently nucleate actin polymerization with or without profilin, can cap the barbed end of AFs, and can bind and bundle both AFs and MTs. OsFH15 can also crosslink AFs with MTs, and preferentially bind MTs to AFs. These results demonstrated that OsFH15 played an important role in grain-size control by affecting cell expansion through regulating AFs and MTs.
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Affiliation(s)
- Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- 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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35
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Non diaphanous formin delphilin acts as a barbed end capping protein. Exp Cell Res 2017; 357:163-169. [PMID: 28527698 DOI: 10.1016/j.yexcr.2017.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 05/09/2017] [Accepted: 05/14/2017] [Indexed: 10/19/2022]
Abstract
Formins are multi domain proteins present ubiquitously in all eukaryotes from lower fungi to higher vertebrates. Formins are characterized by the presence of formin homology domain-2 (FH2) and formin homology domain-1 (FH1). There are fifteen different formins present in mouse and human. Among these metazoan formins, Delphilin is a unique formin having two PDZ domains at the N-terminus and FH1, FH2 domain at the C-terminus respectively. In this study we observed that Delphilin binds to actin filaments, and Delphilin inhibits actin filament elongation like barbed end capping protein CapZ. In vitro, Delphilin stabilized actin filaments by inhibiting actin filament depolymerisation. Therefore, our study demonstrates Delphilin as an actin-filament capping protein.
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36
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Li S, Dong H, Pei W, Liu C, Zhang S, Sun T, Xue X, Ren H. LlFH1-mediated interaction between actin fringe and exocytic vesicles is involved in pollen tube tip growth. THE NEW PHYTOLOGIST 2017; 214:745-761. [PMID: 28092406 DOI: 10.1111/nph.14395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/16/2016] [Indexed: 05/15/2023]
Abstract
Pollen tube tip growth is an extreme form of polarized cell growth, which requires polarized exocytosis based on a dynamic actin cytoskeleton. However, the molecular basis for the connection between actin filaments and exocytic vesicles is unclear. Here, we identified a Lilium longiflorum pollen-specific formin (LlFH1) and found that it localized at the apical vesicles and plasma membrane (PM). Overexpression of LlFH1 induced excessive actin cables in the tube tip region, and downregulation of LlFH1 eliminated the actin fringe. Fluorescence recovery after photobleaching (FRAP) analysis revealed that LlFH1-labeled exocytic vesicles exhibited an initial accumulation at the shoulder of the apex and coincided with the leading edge of the actin fringe. Time-lapse analysis suggested that nascent actin filaments followed the emergence of the apical vesicles, implying that LlFH1 at apical vesicles could initiate actin polymerization. Biochemical assays showed that LlFH1 FH1FH2 could nucleate actin polymerization, but then capped the actin filament at the barbed end and inhibited its elongation. However, in the presence of lily profilins, LlFH1 FH1FH2 could accelerate barbed-end actin elongation. In addition, LlFH1 FH1FH2 was able to bundle actin filaments. Thus, we propose that LlFH1 and profilin coordinate the interaction between the actin fringe and exocytic vesicle trafficking during pollen tube growth of lily.
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Affiliation(s)
- Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Huaijian Dong
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - 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
| | - Chaonan Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- 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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37
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Zhang S, Liu C, Wang J, Ren Z, Staiger CJ, Ren H. A Processive Arabidopsis Formin Modulates Actin Filament Dynamics in Association with Profilin. MOLECULAR PLANT 2016; 9:900-10. [PMID: 26996265 DOI: 10.1016/j.molp.2016.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/28/2016] [Accepted: 03/04/2016] [Indexed: 05/08/2023]
Abstract
Formins are conserved regulators of actin cytoskeletal organization and dynamics that have been implicated to be important for cell division and cell polarity. The mechanism by which diverse formins regulate actin dynamics in plants is still not well understood. Using in vitro single-molecule imaging technology, we directly observed that the FH1-FH2 domain of an Arabidopsis thaliana formin, AtFH14, processively attaches to the barbed end of actin filaments as a dimer and slows their elongation rate by 90%. The attachment persistence of FH1-FH2 is concentration dependent. Furthermore, by use of the triple-color total internal reflection fluorescence microscopy, we found that ABP29, a barbed-end capping protein, competes with FH1-FH2 at the filament barbed end, where its binding is mutually exclusive with AtFH14. In the presence of different plant profilin isoforms, FH1-FH2 enhances filament elongation rates from about 10 to 42 times. Filaments buckle when FH1-FH2 is anchored specifically to cover slides, further indicating that AtFH14 moves processively on the elongating barbed end. At high concentration, AtFH14 bundles actin filaments randomly into antiparallel or parallel spindle-like structures; however, the FH1-FH2-mediated bundles become thinner and longer in the presence of plant profilins. This is the direct demonstration of a processive formin from plants. Our results also illuminate the molecular mechanism of AtFH14 in regulating actin dynamics via association with profilin.
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Affiliation(s)
- Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Chang Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jiaojiao Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Zhanhong Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Christopher J Staiger
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Research Building, West Lafayette, IN 47907-2064, USA
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China.
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Rosero A, Oulehlová D, Stillerová L, Schiebertová P, Grunt M, Žárský V, Cvrčková F. Arabidopsis FH1 Formin Affects Cotyledon Pavement Cell Shape by Modulating Cytoskeleton Dynamics. PLANT & CELL PHYSIOLOGY 2016; 57:488-504. [PMID: 26738547 DOI: 10.1093/pcp/pcv209] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 12/24/2015] [Indexed: 05/03/2023]
Abstract
Plant cell morphogenesis involves concerted rearrangements of microtubules and actin microfilaments. We previously reported that FH1, the main Arabidopsis thaliana housekeeping Class I membrane-anchored formin, contributes to actin dynamics and microtubule stability in rhizodermis cells. Here we examine the effects of mutations affecting FH1 (At3g25500) on cell morphogenesis and above-ground organ development in seedlings, as well as on cytoskeletal organization and dynamics, using a combination of confocal and variable angle epifluorescence microscopy with a pharmacological approach. Homozygous fh1 mutants exhibited cotyledon epinasty and had larger cotyledon pavement cells with more pronounced lobes than the wild type. The pavement cell shape alterations were enhanced by expression of the fluorescent microtubule marker GFP-microtubule-associated protein 4 (MAP4). Mutant cotyledon pavement cells exhibited reduced density and increased stability of microfilament bundles, as well as enhanced dynamics of microtubules. Analogous results were also obtained upon treatments with the formin inhibitor SMIFH2 (small molecule inhibitor of formin homology 2 domains). Pavement cell shape in wild-type (wt) and fh1 plants in some situations exhibited a differential response towards anti-cytoskeletal drugs, especially the microtubule disruptor oryzalin. Our observations indicate that FH1 participates in the control of microtubule dynamics, possibly via its effects on actin, subsequently influencing cell morphogenesis and macroscopic organ development.
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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 Colombian Institute for Agricultural Research-CORPOICA-Turipana, Km 13 via Monteria, Cereté, Cordoba, Colombia Department of Cell Biology, Faculty of Science, Palacký University Olomouc, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 586/11, CZ 783 71 Olomouc-Holice, Czech Republic
| | - Denisa Oulehlová
- 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
| | - Lenka Stillerová
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Praha 2, Czech Republic
| | - Petra Schiebertová
- Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, CZ 128 44 Praha 2, Czech Republic
| | - Michal Grunt
- 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
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Borassi C, Sede AR, Mecchia MA, Salgado Salter JD, Marzol E, Muschietti JP, Estevez JM. An update on cell surface proteins containing extensin-motifs. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:477-87. [PMID: 26475923 DOI: 10.1093/jxb/erv455] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In recent years it has become clear that there are several molecular links that interconnect the plant cell surface continuum, which is highly important in many biological processes such as plant growth, development, and interaction with the environment. The plant cell surface continuum can be defined as the space that contains and interlinks the cell wall, plasma membrane and cytoskeleton compartments. In this review, we provide an updated view of cell surface proteins that include modular domains with an extensin (EXT)-motif followed by a cytoplasmic kinase-like domain, known as PERKs (for proline-rich extensin-like receptor kinases); with an EXT-motif and an actin binding domain, known as formins; and with extracellular hybrid-EXTs. We focus our attention on the EXT-motifs with the short sequence Ser-Pro(3-5), which is found in several different protein contexts within the same extracellular space, highlighting a putative conserved structural and functional role. A closer understanding of the dynamic regulation of plant cell surface continuum and its relationship with the downstream signalling cascade is a crucial forthcoming challenge.
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Affiliation(s)
- Cecilia Borassi
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Ana R Sede
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina
| | - Martin A Mecchia
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina
| | - Juan D Salgado Salter
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Eliana Marzol
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Jorge P Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina. Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina.
| | - Jose M Estevez
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina.
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40
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Kijima ST, Hirose K, Kong SG, Wada M, Uyeda TQP. Distinct Biochemical Properties of Arabidopsis thaliana Actin Isoforms. PLANT & CELL PHYSIOLOGY 2016; 57:46-56. [PMID: 26578694 DOI: 10.1093/pcp/pcv176] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 11/03/2015] [Indexed: 05/20/2023]
Abstract
Plants and animals express multiple actin isoforms in a manner that is dependent on tissues, organs and the stage of development. Previous genetic analyses suggested that individual actin isoforms have specific roles in cells, but there is little biochemical evidence to support this hypothesis. In this study, we purified four recombinant Arabidopsis actin isoforms, two major vegetative actin isoforms, ACT2 and ACT7, and two major reproductive isoforms, ACT1 and ACT11, and characterized them biochemically. Phalloidin bound normally to the filaments of the two reproductive actins as well as to the filaments of skeletal muscle actin. However, phalloidin bound only weakly to ACT7 filaments and hardly at all to ACT2 filaments, despite the conserved sequence of the phalloidin-binding site. Polymerization and phosphate release rates among these four actin isoforms were also significantly different. Moreover, interactions with profilin (PRF) were also different among the four Arabidopsis actin isoforms. PRF1 and PRF2 inhibited the polymerization of ACT1, ACT11 and ACT7, while ACT2 was only weakly affected. Plant actin isoforms have different biochemical properties. This result supports the idea that actin isoforms play specific roles to achieve multiple cell functions.
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Affiliation(s)
- Saku T Kijima
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, 305-8562 Japan Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572 Japan
| | - Keiko Hirose
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, 305-8562 Japan Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572 Japan
| | - Sam-Geun Kong
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581 Japan Present address: Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582 Japan and Research Center for Live-Protein Dynamics, Kyushu University, Fukuoka, 812-8582 Japan
| | - Masamitsu Wada
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581 Japan Pesent address: Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, 192-0397 Japan
| | - Taro Q P Uyeda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, 305-8562 Japan Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572 Japan
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Cao L, Henty-Ridilla JL, Blanchoin L, Staiger CJ. Profilin-Dependent Nucleation and Assembly of Actin Filaments Controls Cell Elongation in Arabidopsis. PLANT PHYSIOLOGY 2016; 170:220-33. [PMID: 26574597 PMCID: PMC4704583 DOI: 10.1104/pp.15.01321] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/16/2015] [Indexed: 05/19/2023]
Abstract
Actin filaments in plant cells are incredibly dynamic; they undergo incessant remodeling and assembly or disassembly within seconds. These dynamic events are choreographed by a plethora of actin-binding proteins, but the exact mechanisms are poorly understood. Here, we dissect the contribution of Arabidopsis (Arabidopsis thaliana) PROFILIN1 (PRF1), a conserved actin monomer-binding protein, to actin organization and single filament dynamics during axial cell expansion of living epidermal cells. We found that reduced PRF1 levels enhanced cell and organ growth. Surprisingly, we observed that the overall frequency of nucleation events in prf1 mutants was dramatically decreased and that a subpopulation of actin filaments that assemble at high rates was reduced. To test whether profilin cooperates with plant formin proteins to execute actin nucleation and rapid filament elongation in cells, we used a pharmacological approach. Here, we used Small Molecule Inhibitor of Formin FH2 (SMIFH2), after validating its mode of action on a plant formin in vitro, and observed a reduced nucleation frequency of actin filaments in live cells. Treatment of wild-type epidermal cells with SMIFH2 mimicked the phenotype of prf1 mutants, and the nucleation frequency in prf1-2 mutant was completely insensitive to these treatments. Our data provide compelling evidence that PRF1 coordinates the stochastic dynamic properties of actin filaments by modulating formin-mediated actin nucleation and assembly during plant cell expansion.
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Affiliation(s)
- Lingyan Cao
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064 (L.C., J.L.H.-R., C.J.S.); andInstitut de Recherches en Technologie et Sciences pour le Vivant, Commissariat á l'Engergie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Joseph Fourier, CEA Grenoble, F-38054 Grenoble cedex 9, France (L.B.)
| | - Jessica L Henty-Ridilla
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064 (L.C., J.L.H.-R., C.J.S.); andInstitut de Recherches en Technologie et Sciences pour le Vivant, Commissariat á l'Engergie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Joseph Fourier, CEA Grenoble, F-38054 Grenoble cedex 9, France (L.B.)
| | - Laurent Blanchoin
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064 (L.C., J.L.H.-R., C.J.S.); andInstitut de Recherches en Technologie et Sciences pour le Vivant, Commissariat á l'Engergie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Joseph Fourier, CEA Grenoble, F-38054 Grenoble cedex 9, France (L.B.)
| | - Christopher J Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064 (L.C., J.L.H.-R., C.J.S.); andInstitut de Recherches en Technologie et Sciences pour le Vivant, Commissariat á l'Engergie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Joseph Fourier, CEA Grenoble, F-38054 Grenoble cedex 9, France (L.B.)
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Wu S, Xie Y, Zhang J, Ren Y, Zhang X, Wang J, Guo X, Wu F, Sheng P, Wang J, Wu C, Wang H, Huang S, Wan J. VLN2 Regulates Plant Architecture by Affecting Microfilament Dynamics and Polar Auxin Transport in Rice. THE PLANT CELL 2015; 27:2829-45. [PMID: 26486445 PMCID: PMC4682327 DOI: 10.1105/tpc.15.00581] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/02/2015] [Indexed: 05/07/2023]
Abstract
As a fundamental and dynamic cytoskeleton network, microfilaments (MFs) are regulated by diverse actin binding proteins (ABPs). Villins are one type of ABPs belonging to the villin/gelsolin superfamily, and their function is poorly understood in monocotyledonous plants. Here, we report the isolation and characterization of a rice (Oryza sativa) mutant defective in VILLIN2 (VLN2), which exhibits malformed organs, including twisted roots and shoots at the seedling stage. Cellular examination revealed that the twisted phenotype of the vln2 mutant is mainly caused by asymmetrical expansion of cells on the opposite sides of an organ. VLN2 is preferentially expressed in growing tissues, consistent with a role in regulating cell expansion in developing organs. Biochemically, VLN2 exhibits conserved actin filament bundling, severing and capping activities in vitro, with bundling and stabilizing activity being confirmed in vivo. In line with these findings, the vln2 mutant plants exhibit a more dynamic actin cytoskeleton network than the wild type. We show that vln2 mutant plants exhibit a hypersensitive gravitropic response, faster recycling of PIN2 (an auxin efflux carrier), and altered auxin distribution. Together, our results demonstrate that VLN2 plays an important role in regulating plant architecture by modulating MF dynamics, recycling of PIN2, and polar auxin transport.
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Affiliation(s)
- Shengyang Wu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yurong Xie
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Junjie Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yulong Ren
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xin Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jiulin Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiuping Guo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Fuqing Wu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Peike Sheng
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Juan Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chuanyin Wu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Haiyang Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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43
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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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Zhu J, Geisler M. Keeping it all together: auxin-actin crosstalk in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4983-98. [PMID: 26085676 DOI: 10.1093/jxb/erv308] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Polar auxin transport and the action of the actin cytoskeleton are tightly interconnected, which is documented by the finding that auxin transporters reach their final destination by active movement of secretory vesicles along F-actin tracks. Moreover, auxin transporter polarity and flexibility is thought to depend on transporter cycling that requires endocytosis and exocytosis of vesicles. In this context, we have reviewed the current literature on an involvement of the actin cytoskeleton in polar auxin transport and identify known similarities and differences in its structure, function and dynamics in comparison to non-plant organisms. By describing how auxin modulates actin expression and actin organization and how actin and its stability affects auxin-transporter endocytosis and recycling, we discuss the current knowledge on regulatory auxin-actin feedback loops. We focus on known effects of auxin and of auxin transport inhibitors on the stability and organization of actin and examine the functionality of auxin and/or auxin transport inhibitor-binding proteins with respect to their suitability to integrate auxin/auxin transport inhibitor action. Finally, we indicate current difficulties in the interpretation of organ, time and concentration-dependent auxin/auxin transport inhibitor treatments and formulate simple future experimental guidelines.
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Affiliation(s)
- Jinsheng Zhu
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
| | - Markus Geisler
- University of Fribourg, Department of Biology-Plant Biology, CH-1700 Fribourg, Switzerland
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45
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Zhou Z, Shi H, Chen B, Zhang R, Huang S, Fu Y. Arabidopsis RIC1 Severs Actin Filaments at the Apex to Regulate Pollen Tube Growth. THE PLANT CELL 2015; 27:1140-61. [PMID: 25804540 PMCID: PMC4558691 DOI: 10.1105/tpc.114.135400] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/13/2015] [Accepted: 03/01/2015] [Indexed: 05/18/2023]
Abstract
Pollen tubes deliver sperms to the ovule for fertilization via tip growth. The rapid turnover of F-actin in pollen tube tips plays an important role in this process. In this study, we demonstrate that Arabidopsis thaliana RIC1, a member of the ROP-interactive CRIB motif-containing protein family, regulates pollen tube growth via its F-actin severing activity. Knockout of RIC1 enhanced pollen tube elongation, while overexpression of RIC1 dramatically reduced tube growth. Pharmacological analysis indicated that RIC1 affected F-actin dynamics in pollen tubes. In vitro biochemical assays revealed that RIC1 directly bound and severed F-actin in the presence of Ca(2+) in addition to interfering with F-actin turnover by capping F-actin at the barbed ends. In vivo, RIC1 localized primarily to the apical plasma membrane (PM) of pollen tubes. The level of RIC1 at the apical PM oscillated during pollen tube growth. The frequency of F-actin severing at the apex was notably decreased in ric1-1 pollen tubes but was increased in pollen tubes overexpressing RIC1. We propose that RIC1 regulates F-actin dynamics at the apical PM as well as the cytosol by severing F-actin and capping the barbed ends in the cytoplasm, establishing a novel mechanism that underlies the regulation of pollen tube growth.
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Affiliation(s)
- Zhenzhen Zhou
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Haifan Shi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Binqing Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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46
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Abstract
Advances in microscopy techniques applied to living cells have dramatically transformed our view of the actin cytoskeleton as a framework for cellular processes. Conventional fluorescence imaging and static analyses are useful for quantifying cellular architecture and the network of filaments that support vesicle trafficking, organelle movement, and response to biotic stress. However, new imaging techniques have revealed remarkably dynamic features of individual actin filaments and the mechanisms that underpin their construction and turnover. In this review, we briefly summarize knowledge about actin and actin-binding proteins in plant systems. We focus on the quantitative properties of the turnover of individual actin filaments, highlight actin-binding proteins that participate in actin dynamics, and summarize the current genetic evidence that has been used to dissect specific aspects of the stochastic dynamics model. Finally, we describe some signaling pathways in which recent data implicate changes in actin filament dynamics and the associated cytoplasmic responses.
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Affiliation(s)
- Jiejie Li
- Department of Biological Sciences and
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47
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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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48
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Grierson C, Nielsen E, Ketelaarc T, Schiefelbein J. Root hairs. THE ARABIDOPSIS BOOK 2014; 12:e0172. [PMID: 24982600 PMCID: PMC4075452 DOI: 10.1199/tab.0172] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology.
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Affiliation(s)
- Claire Grierson
- School of Biological Sciences, University of Bristol, Bristol, UK BS8 1UG
| | - Erik Nielsen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA 48109
| | - Tijs Ketelaarc
- Laboratory of Cell Biology, Wageningen University, 6708 PB Wageningen, The Netherlands
| | - John Schiefelbein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA 48109
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49
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Bilancia CG, Winkelman JD, Tsygankov D, Nowotarski SH, Sees JA, Comber K, Evans I, Lakhani V, Wood W, Elston TC, Kovar DR, Peifer M. Enabled negatively regulates diaphanous-driven actin dynamics in vitro and in vivo. Dev Cell 2014; 28:394-408. [PMID: 24576424 PMCID: PMC3992947 DOI: 10.1016/j.devcel.2014.01.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 12/20/2013] [Accepted: 01/15/2014] [Indexed: 11/03/2022]
Abstract
Actin regulators facilitate cell migration by controlling cell protrusion architecture and dynamics. As the behavior of individual actin regulators becomes clear, we must address why cells require multiple regulators with similar functions and how they cooperate to create diverse protrusions. We characterized Diaphanous (Dia) and Enabled (Ena) as a model, using complementary approaches: cell culture, biophysical analysis, and Drosophila morphogenesis. We found that Dia and Ena have distinct biochemical properties that contribute to the different protrusion morphologies each induces. Dia is a more processive, faster elongator, paralleling the long, stable filopodia it induces in vivo, while Ena promotes filopodia with more dynamic changes in number, length, and lifetime. Acting together, Ena and Dia induce protrusions distinct from those induced by either alone, with Ena reducing Dia-driven protrusion length and number. Consistent with this, EnaEVH1 binds Dia directly and inhibits DiaFH1FH2-mediated nucleation in vitro. Finally, Ena rescues hemocyte migration defects caused by activated Dia. Dia and Ena differ biochemically, promoting distinct filopodia dynamics Dia and Ena colocalization negatively regulates filopodia Ena’s EVH1 binds Dia’s FH1 and reduces Dia-driven filopodia and actin nucleation Ena rescues DiaΔDAD inhibition of hemocyte migration speed to wounds in vivo
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Affiliation(s)
- Colleen G Bilancia
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jonathan D Winkelman
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Denis Tsygankov
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stephanie H Nowotarski
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jennifer A Sees
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Kate Comber
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Iwan Evans
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Vinal Lakhani
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Will Wood
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Mark Peifer
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Rosado M, Barber CF, Berciu C, Feldman S, Birren SJ, Nicastro D, Goode BL. Critical roles for multiple formins during cardiac myofibril development and repair. Mol Biol Cell 2014; 25:811-27. [PMID: 24430873 PMCID: PMC3952851 DOI: 10.1091/mbc.e13-08-0443] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/13/2013] [Accepted: 01/09/2014] [Indexed: 12/31/2022] Open
Abstract
Cardiac and skeletal muscle function depends on the proper formation of myofibrils, which are tandem arrays of highly organized actomyosin contractile units called sarcomeres. How the architecture of these colossal molecular assemblages is established during development and maintained over the lifetime of an animal is poorly understood. We investigate the potential roles in myofibril formation and repair of formin proteins, which are encoded by 15 different genes in mammals. Using quantitative real-time PCR analysis, we find that 13 formins are differentially expressed in mouse hearts during postnatal development. Seven formins immunolocalize to sarcomeres in diverse patterns, suggesting that they have a variety of functional roles. Using RNA interference silencing, we find that the formins mDia2, DAAM1, FMNL1, and FMNL2 are required nonredundantly for myofibrillogenesis. Knockdown phenotypes include global loss of myofibril organization and defective sarcomeric ultrastructure. Finally, our analysis reveals an unanticipated requirement specifically for FMNL1 and FMNL2 in the repair of damaged myofibrils. Together our data reveal an unexpectedly large number of formins, with diverse localization patterns and nonredundant roles, functioning in myofibril development and maintenance, and provide the first evidence of actin assembly factors being required to repair myofibrils.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Animals
- Animals, Newborn
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cell Differentiation
- Formins
- Gene Expression Regulation, Developmental
- Heterocyclic Compounds, 4 or More Rings/pharmacology
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Microfilament Proteins/antagonists & inhibitors
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Microtubule-Associated Proteins/antagonists & inhibitors
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism
- Muscle Development/genetics
- Myocardium/cytology
- Myocardium/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- NADPH Dehydrogenase/antagonists & inhibitors
- NADPH Dehydrogenase/genetics
- NADPH Dehydrogenase/metabolism
- Primary Cell Culture
- Protein Isoforms/antagonists & inhibitors
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Sarcomeres/metabolism
- Sarcomeres/ultrastructure
- Thiazolidines/pharmacology
- Wound Healing/genetics
- rho GTP-Binding Proteins/antagonists & inhibitors
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
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Affiliation(s)
| | | | - Cristina Berciu
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Steven Feldman
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Susan J. Birren
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Daniela Nicastro
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Bruce L. Goode
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
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