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Lucas J, Geisler M. Plant Kinesin Repertoires Expand with New Domain Architecture and Contract with the Loss of Flagella. J Mol Evol 2024:10.1007/s00239-024-10178-9. [PMID: 38926179 DOI: 10.1007/s00239-024-10178-9] [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: 07/10/2023] [Accepted: 05/20/2024] [Indexed: 06/28/2024]
Abstract
Kinesins are eukaryotic microtubule motor proteins subdivided into conserved families with distinct functional roles. While many kinesin families are widespread in eukaryotes, each organismal lineage maintains a unique kinesin repertoire composed of many families with distinct numbers of genes. Previous genomic surveys indicated that land plant kinesin repertoires differ markedly from other eukaryotes. To determine when repertoires diverged during plant evolution, we performed robust phylogenomic analyses of kinesins in 24 representative plants, two algae, two animals, and one yeast. These analyses show that kinesin repertoires expand and contract coincident with major shifts in the biology of algae and land plants. One kinesin family and five subfamilies, each defined by unique domain architectures, emerged in the green algae. Four of those kinesin groups expanded in ancestors of modern land plants, while six other kinesin groups were lost in the ancestors of pollen-bearing plants. Expansions of different kinesin families and subfamilies occurred in moss and angiosperm lineages. Other kinesin families remained stable and did not expand throughout plant evolution. Collectively these data support a radiation of kinesin domain architectures in algae followed by differential positive and negative selection on kinesins families and subfamilies in different lineages of land plants.
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Affiliation(s)
- Jessica Lucas
- Department of Biology, University of Wisconsin-Oshkosh, 800 Algoma Blvd, Oshkosh, WI, 54901, USA.
| | - Matt Geisler
- School of Biological Science, Southern Illinois University, Carbondale, IL, 54901, USA
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2
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Brueggeman JM, Windham IA, Nebenführ A. Nuclear movement in growing Arabidopsis root hairs involves both actin filaments and microtubules. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5388-5399. [PMID: 35554524 DOI: 10.1093/jxb/erac207] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Nuclear migration during growth and development is a conserved phenomenon among many eukaryotic species. In Arabidopsis, movement of the nucleus is important for root hair growth, but the detailed mechanism behind this movement is not well known. Previous studies in different cell types have reported that the myosin XI-I motor protein is responsible for this nuclear movement by attaching to the nuclear transmembrane protein complex WIT1/WIT2. Here, we analyzed nuclear movement in growing root hairs of wild-type, myosin xi-i, and wit1 wit2 Arabidopsis lines in the presence of actin and microtubule-disrupting inhibitors to determine the individual effects of actin filaments and microtubules on nuclear movement. We discovered that forward nuclear movement during root hair growth can occur in the absence of myosin XI-I, suggesting the presence of an alternative actin-based mechanism that mediates rapid nuclear displacements. By quantifying nuclear movements with high temporal resolution during the initial phase of inhibitor treatment, we determined that microtubules work to dampen erratic nuclear movements during root hair growth. We also observed microtubule-dependent backwards nuclear movement when actin filaments were impaired in the absence of myosin XI-I, indicating the presence of complex interactions between the cytoskeletal arrays during nuclear movements in growing root hairs.
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Affiliation(s)
- Justin M Brueggeman
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Ian A Windham
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA
| | - Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
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3
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Hong WJ, Kim EJ, Yoon J, Silva J, Moon S, Min CW, Cho LH, Kim ST, Park SK, Kim YJ, Jung KH. A myosin XI adaptor, TAPE, is essential for pollen tube elongation in rice. PLANT PHYSIOLOGY 2022; 190:562-575. [PMID: 35736513 PMCID: PMC9434255 DOI: 10.1093/plphys/kiac299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Pollen tube (PT) elongation is important for double fertilization in angiosperms and affects the seed-setting rate and, therefore, crop productivity. Compared to Arabidopsis (Arabidopsis thaliana L.), information on PT elongation in rice (Oryza sativa L.) is limited by the difficulty in obtaining homozygous mutants. In a screen of T-DNA insertional mutants, we identified a mutant in the Tethering protein of actomyosin transport in pollen tube elongation (TAPE) gene with an unusual segregation ratio by genotyping analysis. A CRISPR/Cas9 knockout mutant of TAPE that produced a short PT was sterile, and TAPE was expressed specifically in pollen grains. TAPE is a homolog of a myosin XI adaptor in Arabidopsis with three tetratricopeptide repeat and Phox and Bem1 protein domains. TAPE showed latrunculin B-sensitive, actin-dependent localization to the endoplasmic reticulum. Yeast two-hybrid screening and transcriptome analysis revealed that TAPE interacted with pollen-specific LIM protein 2b and elongation factor 1-alpha. Loss of TAPE affected transcription of 1,259 genes, especially genes related to cell organization, which were downregulated. In summary, TAPE encodes a myosin XI adaptor essential for rice PT elongation.
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Affiliation(s)
- Woo-Jong Hong
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Eui-Jung Kim
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Jinmi Yoon
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Jeniffer Silva
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Sunok Moon
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Cheol Woo Min
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Lae-Hyeon Cho
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Sun Tae Kim
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Soon Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Yu-Jin Kim
- Authors for correspondence: (Y.-J.K.); (K.-H.J.)
| | - Ki-Hong Jung
- Authors for correspondence: (Y.-J.K.); (K.-H.J.)
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Biel A, Moser M, Groves NR, Meier I. Distinct Roles for KASH Proteins SINE1 and SINE2 in Guard Cell Actin Reorganization, Calcium Oscillations, and Vacuolar Remodeling. FRONTIERS IN PLANT SCIENCE 2022; 13:784342. [PMID: 35599883 PMCID: PMC9120628 DOI: 10.3389/fpls.2022.784342] [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: 09/27/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex is a protein complex spanning the inner and outer membranes of the nuclear envelope. Outer nuclear membrane KASH proteins interact in the nuclear envelope lumen with inner nuclear membrane SUN proteins. The paralogous Arabidopsis KASH proteins SINE1 and SINE2 function during stomatal dynamics induced by light-dark transitions and ABA. Previous studies have shown F-actin organization, cytoplasmic calcium (Ca2+) oscillations, and vacuolar morphology changes are involved in ABA-induced stomatal closure. Here, we show that SINE1 and SINE2 are both required for actin pattern changes during ABA-induced stomatal closure, but influence different, temporally distinguishable steps. External Ca2+ partially overrides the mutant defects. ABA-induced cytoplasmic Ca2+ oscillations are diminished in sine2-1 but not sine1-1, and this defect can be rescued by both exogenous Ca2+ and F-actin depolymerization. We show first evidence for nuclear Ca2+ oscillations during ABA-induced stomatal closure, which are disrupted in sine2-1. Vacuolar fragmentation is impaired in both mutants and is partially rescued by F-actin depolymerization. Together, these data indicate distinct roles for SINE1 and SINE2 upstream of this network of players involved in ABA-based stomatal closure, suggesting a role for the nuclear surface in guard cell ABA signaling.
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Affiliation(s)
- Alecia Biel
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States
| | - Morgan Moser
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States
| | - Norman R. Groves
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
- Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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5
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Cropano C, Manzanares C, Yates S, Copetti D, Do Canto J, Lübberstedt T, Koch M, Studer B. Identification of Candidate Genes for Self-Compatibility in Perennial Ryegrass ( Lolium perenne L.). FRONTIERS IN PLANT SCIENCE 2021; 12:707901. [PMID: 34721449 PMCID: PMC8554087 DOI: 10.3389/fpls.2021.707901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/30/2021] [Indexed: 05/10/2023]
Abstract
Self-incompatibility (SI) is a genetic mechanism preventing self-pollination in ~40% of plant species. Two multiallelic loci, called S and Z, control the gametophytic SI system of the grass family (Poaceae), which contains all major forage grasses. Loci independent from S and Z have been reported to disrupt SI and lead to self-compatibility (SC). A locus causing SC in perennial ryegrass (Lolium perenne L.) was previously mapped on linkage group (LG) 5 in an F2 population segregating for SC. Using a subset of the same population (n = 68), we first performed low-resolution quantitative trait locus (QTL) mapping to exclude the presence of additional, previously undetected contributors to SC. The previously reported QTL on LG 5 explained 38.4% of the phenotypic variation, and no significant contribution from other genomic regions was found. This was verified by the presence of significantly distorted markers in the region overlapping with the QTL. Second, we fine mapped the QTL to 0.26 centimorgan (cM) using additional 2,056 plants and 23 novel sequence-based markers. Using Italian ryegrass (Lolium multiflorum Lam.) genome assembly as a reference, the markers flanking SC were estimated to span a ~3 Mb region encoding for 57 predicted genes. Among these, seven genes were proposed as relevant candidate genes based on their annotation and function described in previous studies. Our study is a step forward to identify SC genes in forage grasses and provides diagnostic markers for marker-assisted introgression of SC into elite germplasm.
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Affiliation(s)
- Claudio Cropano
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
- Deutsche Saatveredelung AG, Lippstadt, Germany
| | - Chloé Manzanares
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Steven Yates
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Dario Copetti
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Javier Do Canto
- Instituto Nacional de Investigación Agropecuaria, Tacuarembó, Uruguay
| | | | | | - Bruno Studer
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
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Schattner S, Schattner J, Munder F, Höppe E, Walter WJ. A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Arabidopsis thaliana Pollen Tubes by Kinesins With Calponin Homology Domain. FRONTIERS IN PLANT SCIENCE 2021; 11:601282. [PMID: 33664751 PMCID: PMC7921805 DOI: 10.3389/fpls.2020.601282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/28/2020] [Indexed: 05/16/2023]
Abstract
Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses. Until now, it is under debate which components of the plant cytoskeleton govern this mechanism. The sperm cells are interconnected and linked to the vegetative nucleus via a cytoplasmic projection, thus forming the male germ unit. This led to the common hypothesis that the vegetative nucleus is actively transported via myosin motors along actin cables while pulling along the sperm cells as passive cargo. In this study, however, we show that upon occasional germ unit disassembly, the sperm cells are transported independently and still follow the same bidirectional movement pattern. Moreover, we found that the net movement of sperm cells results from a combination of both longer and faster runs toward the pollen tube apex. We propose that the observed saltatory movement can be explained by the function of kinesins with calponin homology domain (KCH). This subgroup of the kinesin-14 family actively links actin filaments and microtubules. Based on KCH's specific properties derived from in vitro experiments, we built a tug-of-war model that could reproduce the characteristic sperm cell movement in pollen tubes.
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Affiliation(s)
- Saskia Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Jan Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Fabian Munder
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Eva Höppe
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Wilhelm J. Walter
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
- Department Medicine, Health and Medical University Potsdam, Potsdam, Germany
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7
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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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8
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Kershaw S, Morgan DJ, Boyd J, Spiller DG, Kitchen G, Zindy E, Iqbal M, Rattray M, Sanderson CM, Brass A, Jorgensen C, Hussell T, Matthews LC, Ray DW. Glucocorticoids rapidly inhibit cell migration through a novel, non-transcriptional HDAC6 pathway. J Cell Sci 2020; 133:jcs242842. [PMID: 32381682 PMCID: PMC7295589 DOI: 10.1242/jcs.242842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Glucocorticoids (GCs) act through the glucocorticoid receptor (GR, also known as NR3C1) to regulate immunity, energy metabolism and tissue repair. Upon ligand binding, activated GR mediates cellular effects by regulating gene expression, but some GR effects can occur rapidly without new transcription. Here, we show that GCs rapidly inhibit cell migration, in response to both GR agonist and antagonist ligand binding. The inhibitory effect on migration is prevented by GR knockdown with siRNA, confirming GR specificity, but not by actinomycin D treatment, suggesting a non-transcriptional mechanism. We identified a rapid onset increase in microtubule polymerisation following GC treatment, identifying cytoskeletal stabilisation as the likely mechanism of action. HDAC6 overexpression, but not knockdown of αTAT1, rescued the GC effect, implicating HDAC6 as the GR effector. Consistent with this hypothesis, ligand-dependent cytoplasmic interaction between GR and HDAC6 was demonstrated by quantitative imaging. Taken together, we propose that activated GR inhibits HDAC6 function, and thereby increases the stability of the microtubule network to reduce cell motility. We therefore report a novel, non-transcriptional mechanism whereby GCs impair cell motility through inhibition of HDAC6 and rapid reorganization of the cell architecture.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Stephen Kershaw
- Systems Oncology, Cancer Research UK Manchester Institute, Manchester, SK10 4TG, UK
| | - David J Morgan
- Manchester Collaborative Centre for Inflammation Research, University of Manchester, Manchester, M13 9PT, UK
- Lydia Becker Institute of Immunology and Inflammation University of Manchester, Manchester, M13 9PT, UK
| | - James Boyd
- Division of Cellular and Molecular Physiology, University of Liverpool, Liverpool, L69 3BX, UK
| | - David G Spiller
- Platform Sciences, Enabling Technologies, and Infrastructure, University of Manchester, Manchester, M13 9PT, UK
| | - Gareth Kitchen
- Division of Diabetes, Endocrinology, and Gastroenterology, University of Manchester, Manchester, M13 9PT, UK
| | - Egor Zindy
- Division of Informatics, Imaging, and Data Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Mudassar Iqbal
- Division of Informatics, Imaging, and Data Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Magnus Rattray
- Division of Informatics, Imaging, and Data Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Christopher M Sanderson
- Division of Cellular and Molecular Physiology, University of Liverpool, Liverpool, L69 3BX, UK
| | - Andrew Brass
- Division of Informatics, Imaging, and Data Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Claus Jorgensen
- Systems Oncology, Cancer Research UK Manchester Institute, Manchester, SK10 4TG, UK
| | - Tracy Hussell
- Manchester Collaborative Centre for Inflammation Research, University of Manchester, Manchester, M13 9PT, UK
- Lydia Becker Institute of Immunology and Inflammation University of Manchester, Manchester, M13 9PT, UK
| | - Laura C Matthews
- Leeds Institute of Cancer and Pathology, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - David W Ray
- Division of Diabetes, Endocrinology, and Gastroenterology, University of Manchester, Manchester, M13 9PT, UK
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), University of Oxford, OX3 7LE, and NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, OX3 9DU, UK
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9
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Vavrdová T, Křenek P, Ovečka M, Šamajová O, Floková P, Illešová P, Šnaurová R, Šamaj J, Komis G. Complementary Superresolution Visualization of Composite Plant Microtubule Organization and Dynamics. FRONTIERS IN PLANT SCIENCE 2020; 11:693. [PMID: 32582243 PMCID: PMC7290007 DOI: 10.3389/fpls.2020.00693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 05/01/2020] [Indexed: 05/04/2023]
Abstract
Microtubule bundling is an essential mechanism underlying the biased organization of interphase and mitotic microtubular systems of eukaryotes in ordered arrays. Microtubule bundle formation can be exemplified in plants, where the formation of parallel microtubule systems in the cell cortex or the spindle midzone is largely owing to the microtubule crosslinking activity of a family of microtubule associated proteins, designated as MAP65s. Among the nine members of this family in Arabidopsis thaliana, MAP65-1 and MAP65-2 are ubiquitous and functionally redundant. Crosslinked microtubules can form high-order arrays, which are difficult to track using widefield or confocal laser scanning microscopy approaches. Here, we followed spatiotemporal patterns of MAP65-2 localization in hypocotyl cells of Arabidopsis stably expressing fluorescent protein fusions of MAP65-2 and tubulin. To circumvent imaging difficulties arising from the density of cortical microtubule bundles, we use different superresolution approaches including Airyscan confocal laser scanning microscopy (ACLSM), structured illumination microscopy (SIM), total internal reflection SIM (TIRF-SIM), and photoactivation localization microscopy (PALM). We provide insights into spatiotemporal relations between microtubules and MAP65-2 crossbridges by combining SIM and ACLSM. We obtain further details on MAP65-2 distribution by single molecule localization microscopy (SMLM) imaging of either mEos3.2-MAP65-2 stochastic photoconversion, or eGFP-MAP65-2 stochastic emission fluctuations under specific illumination conditions. Time-dependent dynamics of MAP65-2 were tracked at variable time resolution using SIM, TIRF-SIM, and ACLSM and post-acquisition kymograph analysis. ACLSM imaging further allowed to track end-wise dynamics of microtubules labeled with TUA6-GFP and to correlate them with concomitant fluctuations of MAP65-2 tagged with tagRFP. All different microscopy modules examined herein are accompanied by restrictions in either the spatial resolution achieved, or in the frame rates of image acquisition. PALM imaging is compromised by speed of acquisition. This limitation was partially compensated by exploiting emission fluctuations of eGFP which allowed much higher photon counts at substantially smaller time series compared to mEos3.2. SIM, TIRF-SIM, and ACLSM were the methods of choice to follow the dynamics of MAP65-2 in bundles of different complexity. Conclusively, the combination of different superresolution methods allowed for inferences on the distribution and dynamics of MAP65-2 within microtubule bundles of living A. thaliana cells.
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10
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Wang Y, Clevenger JP, Illa-Berenguer E, Meulia T, van der Knaap E, Sun L. A Comparison of sun, ovate, fs8.1 and Auxin Application on Tomato Fruit Shape and Gene Expression. PLANT & CELL PHYSIOLOGY 2019; 60:1067-1081. [PMID: 30753610 DOI: 10.1093/pcp/pcz024] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 02/07/2019] [Indexed: 05/04/2023]
Abstract
Elongated tomato fruit shape is the result of the action of the fruit shape genes possibly in coordination with the phytohormone auxin. To investigate the possible link between auxin and the fruit shape genes, a series of auxin (2,4-D) treatments were performed on the wild-type and the fruit shape near-isogenic lines (NILs) in Solanum pimpinellifolium accession LA1589 background. Morphological and histological analyses indicated that auxin application approximately 3 weeks before anthesis led to elongated pear-shaped ovaries and fruits, which was mainly attributed to the increase of ovary/fruit proximal end caused by the increase of both cell number and cell size. Fruit shape changes caused by SUN, OVATE and fs8.1 were primarily due to the alterations of cell number along different growth axes. Particularly, SUN caused elongation by extending cell number along the entire proximal-distal axis, whereas OVATE caused fruit elongation in the proximal area, which was most similar to the effect of auxin on ovary shape. Expression analysis of flower buds at different stages in fruit shape NILs indicated that SUN had a stronger impact on the transcriptome than OVATE and fs8.1. The sun NIL differentially expressed genes were enriched in several biological processes, such as lipid metabolism, ion transmembrane and actin cytoskeleton organization. Additionally, SUN also shifted the expression of the auxin-related genes, including those involved in auxin biosynthesis, homeostasis, signal transduction and polar transport, indicating that SUN may regulate ovary/fruit shape through modifying the expression of auxin-related genes very early during the formation of the ovary in the developing flower.
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Affiliation(s)
- Yanping Wang
- College of Horticulture, China Agricultural University, Beijing, P.R. China
- Department of Horticulture and Crop Science, The Ohio State University/OARDC, Wooster, OH, USA
- National Engineering Research Center for Vegetables, Beijing Academy of Agriculture and Forestry Sciences, Beijing, P.R. China
| | - Josh P Clevenger
- Department of Horticulture and Crop Science, The Ohio State University/OARDC, Wooster, OH, USA
- Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Athens, GA, USA
- Center for Applied Genetic Technologies, Mars Wrigley Confectionery, Athens, GA, USA
| | | | - Tea Meulia
- Department of Plant Pathology, Molecular and Cellular Imaging Center, The Ohio State University/OARDC, Wooster, OH, USA
| | - Esther van der Knaap
- Department of Horticulture and Crop Science, The Ohio State University/OARDC, Wooster, OH, USA
- Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Athens, GA, USA
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA, USA
| | - Liang Sun
- College of Horticulture, China Agricultural University, Beijing, P.R. China
- Department of Horticulture and Crop Science, The Ohio State University/OARDC, Wooster, OH, USA
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, P.R. China
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11
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Mitra D, Klemm S, Kumari P, Quegwer J, Möller B, Poeschl Y, Pflug P, Stamm G, Abel S, Bürstenbinder K. Microtubule-associated protein IQ67 DOMAIN5 regulates morphogenesis of leaf pavement cells in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:529-543. [PMID: 30407556 PMCID: PMC6322583 DOI: 10.1093/jxb/ery395] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/22/2018] [Indexed: 05/14/2023]
Abstract
Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation, and cell morphology. Their organization and dynamics are co-ordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization, and biological functions. We show that IQD5 is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis of iqd5 loss-of-function lines reveals functions of IQD5 in pavement cell (PC) shape morphogenesis. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced anisotropic expansion. Lastly, we demonstrate IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays and provide first evidence for important roles for calcium in regulation of PC morphogenesis. Our work identifies IQD5 as a novel player in PC shape regulation and, for the first time, links calcium signaling to developmental processes that regulate anisotropic growth in PCs.
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Affiliation(s)
- Dipannita Mitra
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Sandra Klemm
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Pratibha Kumari
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Jakob Quegwer
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Birgit Möller
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Yvonne Poeschl
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- iDiv, German Integrative Research Center for Biodiversity, Leipzig, Germany
| | - Paul Pflug
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Gina Stamm
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Steffen Abel
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Katharina Bürstenbinder
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
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12
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Mitra D, Klemm S, Kumari P, Quegwer J, Möller B, Poeschl Y, Pflug P, Stamm G, Abel S, Bürstenbinder K. Microtubule-associated protein IQ67 DOMAIN5 regulates morphogenesis of leaf pavement cells in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:529-543. [PMID: 30407556 DOI: 10.1101/268466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/22/2018] [Indexed: 05/23/2023]
Abstract
Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation, and cell morphology. Their organization and dynamics are co-ordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization, and biological functions. We show that IQD5 is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis of iqd5 loss-of-function lines reveals functions of IQD5 in pavement cell (PC) shape morphogenesis. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced anisotropic expansion. Lastly, we demonstrate IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays and provide first evidence for important roles for calcium in regulation of PC morphogenesis. Our work identifies IQD5 as a novel player in PC shape regulation and, for the first time, links calcium signaling to developmental processes that regulate anisotropic growth in PCs.
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Affiliation(s)
- Dipannita Mitra
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Sandra Klemm
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Pratibha Kumari
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Jakob Quegwer
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Birgit Möller
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Yvonne Poeschl
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- iDiv, German Integrative Research Center for Biodiversity, Leipzig, Germany
| | - Paul Pflug
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Gina Stamm
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
| | - Steffen Abel
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Katharina Bürstenbinder
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry (IPB),Halle (Saale), Germany
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13
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Rasmussen CG, Bellinger M. An overview of plant division-plane orientation. THE NEW PHYTOLOGIST 2018; 219:505-512. [PMID: 29701870 DOI: 10.1111/nph.15183] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/20/2018] [Indexed: 05/10/2023]
Abstract
Contents Summary 505 I. Introduction 505 II. Models of plant cell division 505 III. Establishing the division plane 506 IV. Maintaining the division plane during mitosis and cytokinesis 509 Acknowledgements 510 References 510 SUMMARY: Plants, a significant source of planet-wide biomass, have an unique type of cell division in which a new cell wall is constructed de novo inside the cell and guided towards the cell edge to complete division. The elegant control over positioning this new cell wall is essential for proper patterning and development. Plant cells, lacking migration, tightly coordinate division orientation and directed expansion to generate organized shapes. Several emerging lines of evidence suggest that the proteins required for division-plane establishment are distinct from those required for division-plane maintenance. We discuss recent shape-based computational models and mutant analyses that raise questions about, and identify unexpected connections between, the roles of well-known proteins and structures during division-plane orientation.
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Affiliation(s)
- Carolyn G Rasmussen
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Marschal Bellinger
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
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14
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Campion CG, Zaoui K, Verissimo T, Cossette S, Matsuda H, Solban N, Hamet P, Tremblay J. COMMD5/HCaRG Hooks Endosomes on Cytoskeleton and Coordinates EGFR Trafficking. Cell Rep 2018; 24:670-684.e7. [DOI: 10.1016/j.celrep.2018.06.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/16/2018] [Accepted: 06/13/2018] [Indexed: 12/25/2022] Open
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15
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Nebenführ A, Dixit R. Kinesins and Myosins: Molecular Motors that Coordinate Cellular Functions in Plants. ANNUAL REVIEW OF PLANT BIOLOGY 2018; 69:329-361. [PMID: 29489391 PMCID: PMC6653565 DOI: 10.1146/annurev-arplant-042817-040024] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Kinesins and myosins are motor proteins that can move actively along microtubules and actin filaments, respectively. Plants have evolved a unique set of motors that function as regulators and organizers of the cytoskeleton and as drivers of long-distance transport of various cellular components. Recent progress has established the full complement of motors encoded in plant genomes and has revealed valuable insights into the cellular functions of many kinesin and myosin isoforms. Interestingly, several of the motors were found to functionally connect the two cytoskeletal systems and thereby to coordinate their activities. In this review, we discuss the available genetic, cell biological, and biochemical data for each of the plant kinesin and myosin families from the context of their subcellular mechanism of action as well as their physiological function in the whole plant. We particularly emphasize work that illustrates mechanisms by which kinesins and myosins coordinate the activities of the cytoskeletal system.
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Affiliation(s)
- Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840, USA;
| | - Ram Dixit
- Department of Biology and Center for Engineering Mechanobiology, Washington University, St. Louis, Missouri 63130-4899, USA;
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16
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Büttner D. Behind the lines-actions of bacterial type III effector proteins in plant cells. FEMS Microbiol Rev 2018; 40:894-937. [PMID: 28201715 PMCID: PMC5091034 DOI: 10.1093/femsre/fuw026] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/31/2016] [Accepted: 07/03/2016] [Indexed: 01/30/2023] Open
Abstract
Pathogenicity of most Gram-negative plant-pathogenic bacteria depends on the type III secretion (T3S) system, which translocates bacterial effector proteins into plant cells. Type III effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. One major virulence function of type III effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. Type III effectors also interfere with additional plant cellular processes including proteasome-dependent protein degradation, phytohormone signaling, the formation of the cytoskeleton, vesicle transport and gene expression. This review summarizes our current knowledge on the molecular functions of type III effector proteins with known plant target molecules. Furthermore, plant defense strategies for the detection of effector protein activities or effector-triggered alterations in plant targets are discussed.
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Affiliation(s)
- Daniela Büttner
- Genetics Department, Institute of Biology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
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17
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Spiegelman Z, Lee CM, Gallagher KL. KinG Is a Plant-Specific Kinesin That Regulates Both Intra- and Intercellular Movement of SHORT-ROOT. PLANT PHYSIOLOGY 2018; 176:392-405. [PMID: 29122988 PMCID: PMC5761801 DOI: 10.1104/pp.17.01518] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 11/06/2017] [Indexed: 05/09/2023]
Abstract
Both endogenous plant proteins and viral movement proteins associate with microtubules to promote their movement through plasmodesmata. The association of viral movement proteins with microtubules facilitates the formation of virus-associated replication complexes, which are required for the amplification and subsequent spread of the virus. However, the role of microtubules in the intercellular movement of plant proteins is less clear. Here we show that the SHORT-ROOT (SHR) protein, which moves between cells in the root to regulate root radial patterning, interacts with a type-14 kinesin, KINESIN G (KinG). KinG is a calponin homology domain kinesin that directly interacts with the SHR-binding protein SIEL (SHR-INTERACING EMBRYONIC LETHAL) and localizes to both microtubules and actin. Since SIEL and SHR associate with endosomes, we suggest that KinG serves as a linker between SIEL, SHR, and the plant cytoskeleton. Loss of KinG function results in a decrease in the intercellular movement of SHR and an increase in the sensitivity of SHR movement to treatment with oryzalin. Examination of SHR and KinG localization and dynamics in live cells suggests that KinG is a nonmotile kinesin that promotes the pausing of SHR-associated endosomes. We suggest a model in which interaction of KinG with SHR allows for the formation of stable movement complexes that facilitate the cell-to-cell transport of SHR.
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Affiliation(s)
- Ziv Spiegelman
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Chin-Mei Lee
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Kimberly L Gallagher
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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18
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Wang P, Hawkins TJ, Hussey PJ. Connecting membranes to the actin cytoskeleton. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:71-76. [PMID: 28779654 DOI: 10.1016/j.pbi.2017.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/13/2017] [Indexed: 05/10/2023]
Abstract
In plants, the actin cytoskeleton plays a major role in organelle movement, cargo transport, maintaining cell polarity and controlling the morphogenesis of endomembrane systems. All of these events require a direct connection between membrane structures and the cytoskeleton. Our knowledge in this field has been greatly advanced by a few recent discoveries including the identification of the plant specific NETWORKED family of proteins, which can mediate such linkages. Other proteins that are known to regulate actin nucleation and polymerization are also likely to be involved, but many key questions still remain unanswered. In this paper, we will focus on recent research on the interfaces between the actin cytoskeleton and membranes of the endoplasmic reticulum, the vacuole and autophagosomes.
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Affiliation(s)
- Pengwei Wang
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Tim J Hawkins
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
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19
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Huang X, Maisch J, Nick P. Sensory role of actin in auxin-dependent responses of tobacco BY-2. JOURNAL OF PLANT PHYSIOLOGY 2017; 218:6-15. [PMID: 28763708 DOI: 10.1016/j.jplph.2017.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 05/09/2023]
Abstract
Polar auxin transport depends on the polar localization of auxin-efflux carriers. The cycling of these carriers between cell interior and plasma membrane depends on actin. The dynamic of actin not only affects auxin transport, but also changes the auxin-responsiveness. To study the potential link between auxin responsiveness and actin dynamics, we investigated developmental responses of the non-transformed BY-2 (Nicotiana tabacum L. cv Bright Yellow 2) cell line and the transgenic BY-2 strain GF11 (stably transformed BY-2 cells with a GFP-fimbrin actin-binding domain 2 construct). The developmental process was divided into three distinct stages: cell cycling, cell elongation and file disintegration. Several phenotypes were measured to monitor the cellular responses to different concentrations of exogenous natural auxin (Indole-3-acetic acid, IAA). We found that auxin stimulated and prolonged the mitotic activity, and delayed the exit from the proliferation phase. However, both responses were suppressed in the GF11 line. At the stationary phase of the cultivation cycle, auxin strongly accelerated the cell file disintegration. Interestingly, it was not suppressed but progressed to a more complete disintegration in the GF11 line. During the cultivation cycle, we also followed the organization of actin in the GF11 line and did not detect any significant difference in actin organization from untreated control or exogenous IAA treatment. Therefore, our findings indicate that the specific differences observed in the GF11 line must be linked with a function of actin that is not structural. It means that there is a sensory role of actin for auxin signaling.
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Affiliation(s)
- Xiang Huang
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Jan Maisch
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
| | - Peter Nick
- Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg. 4, Gbd. 30.43, (5. OG), 76131 Karlsruhe, Germany.
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20
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Rahamim-Ben Navi L, Tsukerman A, Feldman A, Melamed P, Tomić M, Stojilkovic SS, Boehm U, Seger R, Naor Z. GnRH Induces ERK-Dependent Bleb Formation in Gonadotrope Cells, Involving Recruitment of Members of a GnRH Receptor-Associated Signalosome to the Blebs. Front Endocrinol (Lausanne) 2017; 8:113. [PMID: 28626446 PMCID: PMC5454083 DOI: 10.3389/fendo.2017.00113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We have previously described a signaling complex (signalosome) associated with the GnRH receptor (GnRHR). We now report that GnRH induces bleb formation in the gonadotrope-derived LβT2 cells. The blebs appear within ~2 min at a turnover rate of ~2-3 blebs/min and last for at least 90 min. Formation of the blebs requires active ERK1/2 and RhoA-ROCK but not active c-Src. Although the following ligands stimulate ERK1/2 in LβT2 cells: EGF > GnRH > PMA > cyclic adenosine monophosphate (cAMP), they produced little or no effect on bleb formation as compared to the robust effect of GnRH (GnRH > PMA > cAMP > EGF), indicating that ERK1/2 is required but not sufficient for bleb formation possibly due to compartmentalization. Members of the above mentioned signalosome are recruited to the blebs, some during bleb formation (GnRHR, c-Src, ERK1/2, focal adhesion kinase, paxillin, and tubulin), and some during bleb retraction (vinculin), while F-actin decorates the blebs during retraction. Fluorescence intensity measurements for the above proteins across the cells showed higher intensity in the blebs vs. intracellular area. Moreover, GnRH induces blebs in primary cultures of rat pituitary cells and isolated mouse gonadotropes in an ERK1/2-dependent manner. The novel signalosome-bleb pathway suggests that as with the signalosome, the blebs are apparently involved in cell migration. Hence, we have extended the potential candidates which are involved in the blebs life cycle in general and for the GnRHR in particular.
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Affiliation(s)
- Liat Rahamim-Ben Navi
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Anna Tsukerman
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Alona Feldman
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Philippa Melamed
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Melanija Tomić
- National Institute of Child Health and Human Development, National Institute of Health, Bethesda, MD, United States
| | - Stanko S. Stojilkovic
- National Institute of Child Health and Human Development, National Institute of Health, Bethesda, MD, United States
| | - Ulrich Boehm
- Department of Pharmacology and Toxicology, University of Saarland School of Medicine, Homburg, Germany
| | - Rony Seger
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Zvi Naor
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
- *Correspondence: Zvi Naor,
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21
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Affiliation(s)
- Noriko Inada
- The Graduate School of Biological Sciences, Nara Institute of Science and Technology
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22
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Brochhausen L, Maisch J, Nick P. Break of symmetry in regenerating tobacco protoplasts is independent of nuclear positioning. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:799-812. [PMID: 26898230 DOI: 10.1111/jipb.12469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
Nuclear migration and positioning are crucial for the morphogenesis of plant cells. We addressed the potential role of nuclear positioning for polarity induction using an experimental system based on regenerating protoplasts, where the induction of a cell axis de novo can be followed by quantification of specific regeneration stages. Using overexpression of fluorescently tagged extranuclear (perinuclear actin basket, kinesins with a calponin homology domain (KCH)) as well as intranuclear (histone H2B) factors of nuclear positioning and time-lapse series of the early stages of regeneration, we found that nuclear position is no prerequisite for polarity formation. However, polarity formation and nuclear migration were both modulated in the transgenic lines, indicating that both phenomena depend on factors affecting cytoskeletal tensegrity and chromatin structure. We integrated these findings into a model where retrograde signals are required for polarity induction. These signals travel via the cytoskeleton from the nucleus toward targets at the plasma membrane.
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Affiliation(s)
- Linda Brochhausen
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, D-76133 Karlsruhe, Germany.
| | - Jan Maisch
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, D-76133 Karlsruhe, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, D-76133 Karlsruhe, Germany
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23
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Bretou M, Kumari A, Malbec O, Moreau HD, Obino D, Pierobon P, Randrian V, Sáez PJ, Lennon-Duménil AM. Dynamics of the membrane-cytoskeleton interface in MHC class II-restricted antigen presentation. Immunol Rev 2016; 272:39-51. [DOI: 10.1111/imr.12429] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Marine Bretou
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Anita Kumari
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Odile Malbec
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Hélène D. Moreau
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Dorian Obino
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Paolo Pierobon
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Violaine Randrian
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Pablo J. Sáez
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
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24
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Krtková J, Benáková M, Schwarzerová K. Multifunctional Microtubule-Associated Proteins in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:474. [PMID: 27148302 PMCID: PMC4838777 DOI: 10.3389/fpls.2016.00474] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 03/24/2016] [Indexed: 05/21/2023]
Abstract
Microtubules (MTs) are involved in key processes in plant cells, including cell division, growth and development. MT-interacting proteins modulate MT dynamics and organization, mediating functional and structural interaction of MTs with other cell structures. In addition to conventional microtubule-associated proteins (MAPs) in plants, there are many other MT-binding proteins whose primary function is not related to the regulation of MTs. This review focuses on enzymes, chaperones, or proteins primarily involved in other processes that also bind to MTs. The MT-binding activity of these multifunctional MAPs is often performed only under specific environmental or physiological conditions, or they bind to MTs only as components of a larger MT-binding protein complex. The involvement of multifunctional MAPs in these interactions may underlie physiological and morphogenetic events, e.g., under specific environmental or developmental conditions. Uncovering MT-binding activity of these proteins, although challenging, may contribute to understanding of the novel functions of the MT cytoskeleton in plant biological processes.
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Affiliation(s)
- Jana Krtková
- Department of Biology, University of WashingtonSeattle, WA, USA
- Katerina Schwarzerová Lab, Department of Experimental Plant Biology, Faculty of Science, Charles University in PraguePrague, Czech Republic
| | - Martina Benáková
- Katerina Schwarzerová Lab, Department of Experimental Plant Biology, Faculty of Science, Charles University in PraguePrague, Czech Republic
- Department of Biology, Faculty of Science, University of Hradec KrálovéRokitanského, Czech Republic
| | - Kateřina Schwarzerová
- Katerina Schwarzerová Lab, Department of Experimental Plant Biology, Faculty of Science, Charles University in PraguePrague, Czech Republic
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25
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Takeuchi M, Karahara I, Kajimura N, Takaoka A, Murata K, Misaki K, Yonemura S, Staehelin LA, Mineyuki Y. Single microfilaments mediate the early steps of microtubule bundling during preprophase band formation in onion cotyledon epidermal cells. Mol Biol Cell 2016; 27:1809-20. [PMID: 27053663 PMCID: PMC4884071 DOI: 10.1091/mbc.e15-12-0820] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/30/2016] [Indexed: 12/11/2022] Open
Abstract
The preprophase band (PPB) is a cytokinetic apparatus that determines the site of cell division in plants. It originates as a broad band of microtubules (MTs) in G2 and narrows to demarcate the future division site during late prophase. Studies with fluorescent probes have shown that PPBs contain F-actin during early stages of their development but become actin depleted in late prophase. Although this suggests that actins contribute to the early stages of PPB formation, how actins contribute to PPB-MT organization remains unsolved. To address this question, we used electron tomography to investigate the spatial relationship between microfilaments (MFs) and MTs at different stages of PPB assembly in onion cotyledon epidermal cells. We demonstrate that the PPB actins observed by fluorescence microscopy correspond to short, single MFs. A majority of the MFs are bound to MTs, with a subset forming MT-MF-MT bridging structures. During the later stages of PPB assembly, the MF-mediated links between MTs are displaced by MT-MT linkers as the PPB MT arrays mature into tightly packed MT bundles. On the basis of these observations, we propose that the primary function of actins during PPB formation is to mediate the initial bundling of the PPB MTs.
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Affiliation(s)
- Miyuki Takeuchi
- Graduate School of Life Science, University of Hyogo, Himeji 671-2201, Japan Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan
| | - Ichirou Karahara
- Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Naoko Kajimura
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki 567-0047, Japan
| | - Akio Takaoka
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki 567-0047, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Kazuyo Misaki
- RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | | | - L Andrew Staehelin
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Yoshinobu Mineyuki
- Graduate School of Life Science, University of Hyogo, Himeji 671-2201, Japan
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26
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Hepler PK. The Cytoskeleton and Its Regulation by Calcium and Protons. PLANT PHYSIOLOGY 2016; 170:3-22. [PMID: 26722019 PMCID: PMC4704593 DOI: 10.1104/pp.15.01506] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/28/2015] [Indexed: 05/18/2023]
Abstract
Calcium and protons exert control over the formation and activity of the cytoskeleton, usually by modulating an associated motor protein or one that affects the structural organization of the polymer.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
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27
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Lee YRJ, Qiu W, Liu B. Kinesin motors in plants: from subcellular dynamics to motility regulation. CURRENT OPINION IN PLANT BIOLOGY 2015; 28:120-126. [PMID: 26556761 DOI: 10.1016/j.pbi.2015.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/30/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Plants produce enormous forms of the microtubule (MT)-based motor kinesins that have been inspiring plant cell biologists to uncover their functions in relation to plant growth and development. Subcellular localization of kinesin proteins detected through live-cell imaging or immunofluorescence microscopy has provided great insights into the functions of these motors. Dozens of mitotic kinesins exhibit particularly splendid localization patterns from chromosomes and kinetochores to MT arrays like the preprophase band, spindle poles, the spindle midzone, phragmoplast distal ends, and the phragmoplast midzone. Different subcellular localizations indicate distinct functions of these motors that are yet to be characterized. The localization difference between plant kinesins and their animal counterparts implies mechanistic differences in mitosis and cytokinesis between the two kingdoms. When many forms of kinesins are present simultaneously, it becomes critical that their motility is differentially regulated with spatial and temporal precision. Insights into regulatory mechanisms of motors can often be brought about by in vitro single-molecule biophysical studies. Significant advances are expected in this area in the coming years owing to rapid technological advances that are being brought to various model plants.
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Affiliation(s)
- Yuh-Ru Julie Lee
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Weihong Qiu
- Departments of Physics and Biophysics & Biochemistry, Oregon State University, Covallis, OR 97331, USA
| | - Bo Liu
- Department of Plant Biology, University of California, Davis, CA 95616, USA.
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28
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Havelková L, Nanda G, Martinek J, Bellinvia E, Sikorová L, Šlajcherová K, Seifertová D, Fischer L, Fišerová J, Petrášek J, Schwarzerová K. Arp2/3 complex subunit ARPC2 binds to microtubules. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 241:96-108. [PMID: 26706062 DOI: 10.1016/j.plantsci.2015.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/30/2015] [Accepted: 10/01/2015] [Indexed: 05/03/2023]
Abstract
Arp2/3 complex plays a fundamental role in the nucleation of actin filaments (AFs) in yeasts, plants, and animals. In plants, the aberrant shaping and elongation of several types of epidermal cells observed in Arp2/3 complex knockout plant mutants suggest the importance of Arp2/3-mediated actin nucleation for various morphogenetic processes. Here we show that ARPC2, a core Arp2/3 complex subunit, interacts with both actin filaments (AFs) and microtubules (MTs). Plant GFP-ARPC2 expressed in Nicotiana tabacum BY-2 cells, leaf epidermal cells of Nicotiana benthamiana and root epidermal cells of Arabidopsis thaliana decorated MTs. The interaction with MTs was demonstrated by pharmacological approach selectively interfering with either AFs or MTs dynamics as well as by the in vitro co-sedimentation assays. A putative MT-binding domain of tobacco NtARPC2 protein was identified using the co-sedimentation of several truncated NtARPC2 proteins with MTs. Newly identified MT-binding ability of ARPC2 subunit of Arp2/3 complex may represent a new molecular mechanism of AFs and MTs interaction.
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Affiliation(s)
- Lenka Havelková
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Gitanjali Nanda
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jan Martinek
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Erica Bellinvia
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Lenka Sikorová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Kateřina Šlajcherová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Daniela Seifertová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Lukáš Fischer
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jindřiška Fišerová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jan Petrášek
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Kateřina Schwarzerová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic.
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29
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Dixit R. Kinesin motors: Teamsters' union. NATURE PLANTS 2015; 1:15126. [PMID: 27250679 DOI: 10.1038/nplants.2015.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Ram Dixit
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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30
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Tian J, Han L, Feng Z, Wang G, Liu W, Ma Y, Yu Y, Kong Z. Orchestration of microtubules and the actin cytoskeleton in trichome cell shape determination by a plant-unique kinesin. eLife 2015; 4. [PMID: 26287478 PMCID: PMC4574192 DOI: 10.7554/elife.09351] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/18/2015] [Indexed: 11/13/2022] Open
Abstract
Microtubules (MTs) and actin filaments (F-actin) function cooperatively to regulate plant cell morphogenesis. However, the mechanisms underlying the crosstalk between these two cytoskeletal systems, particularly in cell shape control, remain largely unknown. In this study, we show that introduction of the MyTH4-FERM tandem into KCBP (kinesin-like calmodulin-binding protein) during evolution conferred novel functions. The MyTH4 domain and the FERM domain in the N-terminal tail of KCBP physically bind to MTs and F-actin, respectively. During trichome morphogenesis, KCBP distributes in a specific cortical gradient and concentrates at the branching sites and the apexes of elongating branches, which lack MTs but have cortical F-actin. Further, live-cell imaging and genetic analyses revealed that KCBP acts as a hub integrating MTs and actin filaments to assemble the required cytoskeletal configuration for the unique, polarized diffuse growth pattern during trichome cell morphogenesis. Our findings provide significant insights into the mechanisms underlying cytoskeletal regulation of cell shape determination.
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Affiliation(s)
- Juan Tian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Libo Han
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhidi Feng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Weiwei Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yinping Ma
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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31
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Walter WJ, Machens I, Rafieian F, Diez S. The non-processive rice kinesin-14 OsKCH1 transports actin filaments along microtubules with two distinct velocities. NATURE PLANTS 2015; 1:15111. [PMID: 27250543 DOI: 10.1038/nplants.2015.111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/02/2015] [Indexed: 05/28/2023]
Abstract
Microtubules and actin filaments function coordinately in many cellular processes(1-3). Although much of this coordination is mediated by proteins that statically bridge the two cytoskeletal networks(4-6), kinesin-14 motors with an actin binding calponin homology domain (KCHs) have been discovered as putatively dynamic crosslinkers in plants(7,8). OsKCH1, a KCH from rice, interacts with both microtubules and actin filaments in vivo and in vitro(9). However, it has remained unclear whether this interaction is dynamic or if actin binding reduces or even abolishes the motor's motility on microtubules(10,11). Here, we directly show in vitro that OsKCH1 is a non-processive, minus-end-directed motor that transports actin filaments along microtubules. Interestingly, we observe two distinct transport velocities dependent on the relative orientation of the actin filaments with respect to the microtubules. In addition, torsional compliance measurements on individual molecules reveal low flexibility in OsKCH1. We suggest that the orientation-dependent transport velocities emerge from OsKCH1's low torsional compliance combined with an inherently oriented binding to the actin filament. Together, our results imply a central role of OsKCH1 in the polar orientation of actin filaments along microtubules, and thus a contribution to the organization of the cytoskeletal architecture.
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Affiliation(s)
- Wilhelm J Walter
- Molecular Plant Physiology, Biocentre Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Isabel Machens
- Molecular Plant Physiology, Biocentre Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
| | - Fereshteh Rafieian
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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