1
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Chocano-Coralla EJ, Vidali L. Myosin XI, a model of its conserved role in plant cell tip growth. Biochem Soc Trans 2024; 52:505-515. [PMID: 38629612 DOI: 10.1042/bst20220783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 03/21/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
In eukaryotic cells, organelle and vesicle transport, positioning, and interactions play crucial roles in cytoplasmic organization and function. These processes are governed by intracellular trafficking mechanisms. At the core of that trafficking, the cytoskeleton and directional transport by motor proteins stand out as its key regulators. Plant cell tip growth is a well-studied example of cytoplasm organization by polarization. This polarization, essential for the cell's function, is driven by the cytoskeleton and its associated motors. This review will focus on myosin XI, a molecular motor critical for vesicle trafficking and polarized plant cell growth. We will center our discussion on recent data from the moss Physcomitrium patens and the liverwort Marchantia polymorpha. The biochemical properties and structure of myosin XI in various plant species are discussed, highlighting functional conservation across species. We further explore this conservation of myosin XI function in the process of vesicle transport in tip-growing cells. Existing evidence indicates that myosin XI actively organizes actin filaments in tip-growing cells by a mechanism based on vesicle clustering at their tips. A hypothetical model is presented to explain the essential function of myosin XI in polarized plant cell growth based on vesicle clustering at the tip. The review also provides insight into the in vivo localization and dynamics of myosin XI, emphasizing its role in cytosolic calcium regulation, which influences the polymerization of F-actin. Lastly, we touch upon the need for additional research to elucidate the regulation of myosin function.
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Affiliation(s)
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, U.S.A
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2
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Mathieu D, Bryson AE, Hamberger B, Singan V, Keymanesh K, Wang M, Barry K, Mondo S, Pangilinan J, Koriabine M, Grigoriev IV, Bonito G, Hamberger B. Multilevel analysis between Physcomitrium patens and Mortierellaceae endophytes explores potential long-standing interaction among land plants and fungi. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:304-323. [PMID: 38265362 DOI: 10.1111/tpj.16605] [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: 08/04/2023] [Revised: 11/16/2023] [Accepted: 12/13/2023] [Indexed: 01/25/2024]
Abstract
The model moss species Physcomitrium patens has long been used for studying divergence of land plants spanning from bryophytes to angiosperms. In addition to its phylogenetic relationships, the limited number of differential tissues, and comparable morphology to the earliest embryophytes provide a system to represent basic plant architecture. Based on plant-fungal interactions today, it is hypothesized these kingdoms have a long-standing relationship, predating plant terrestrialization. Mortierellaceae have origins diverging from other land fungi paralleling bryophyte divergence, are related to arbuscular mycorrhizal fungi but are free-living, observed to interact with plants, and can be found in moss microbiomes globally. Due to their parallel origins, we assess here how two Mortierellaceae species, Linnemannia elongata and Benniella erionia, interact with P. patens in coculture. We also assess how Mollicute-related or Burkholderia-related endobacterial symbionts (MRE or BRE) of these fungi impact plant response. Coculture interactions are investigated through high-throughput phenomics, microscopy, RNA-sequencing, differential expression profiling, gene ontology enrichment, and comparisons among 99 other P. patens transcriptomic studies. Here we present new high-throughput approaches for measuring P. patens growth, identify novel expression of over 800 genes that are not expressed on traditional agar media, identify subtle interactions between P. patens and Mortierellaceae, and observe changes to plant-fungal interactions dependent on whether MRE or BRE are present. Our study provides insights into how plants and fungal partners may have interacted based on their communications observed today as well as identifying L. elongata and B. erionia as modern fungal endophytes with P. patens.
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Affiliation(s)
- Davis Mathieu
- Genetics and Genome Science Graduate Program, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Abigail E Bryson
- Genetics and Genome Science Graduate Program, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Britta Hamberger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Vasanth Singan
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Keykhosrow Keymanesh
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Mei Wang
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Kerrie Barry
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Stephen Mondo
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Jasmyn Pangilinan
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Maxim Koriabine
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - Igor V Grigoriev
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, 94720, USA
| | - Gregory Bonito
- Genetics and Genome Science Graduate Program, Michigan State University, East Lansing, Michigan, USA
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Björn Hamberger
- Genetics and Genome Science Graduate Program, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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3
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Yuan G, Gao H, Yang T. Exploring the Role of the Plant Actin Cytoskeleton: From Signaling to Cellular Functions. Int J Mol Sci 2023; 24:15480. [PMID: 37895158 PMCID: PMC10607326 DOI: 10.3390/ijms242015480] [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: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
The plant actin cytoskeleton is characterized by the basic properties of dynamic array, which plays a central role in numerous conserved processes that are required for diverse cellular functions. Here, we focus on how actins and actin-related proteins (ARPs), which represent two classical branches of a greatly diverse superfamily of ATPases, are involved in fundamental functions underlying signal regulation of plant growth and development. Moreover, we review the structure, assembly dynamics, and biological functions of filamentous actin (F-actin) from a molecular perspective. The various accessory proteins known as actin-binding proteins (ABPs) partner with F-actin to finely tune actin dynamics, often in response to various cell signaling pathways. Our understanding of the significance of the actin cytoskeleton in vital cellular activities has been furthered by comparison of conserved functions of actin filaments across different species combined with advanced microscopic techniques and experimental methods. We discuss the current model of the plant actin cytoskeleton, followed by examples of the signaling mechanisms under the supervision of F-actin related to cell morphogenesis, polar growth, and cytoplasmic streaming. Determination of the theoretical basis of how the cytoskeleton works is important in itself and is beneficial to future applications aimed at improving crop biomass and production efficiency.
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Affiliation(s)
| | | | - Tao Yang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; (G.Y.); (H.G.)
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4
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Allan C, Morris RJ, Meisrimler CN. Encoding, transmission, decoding, and specificity of calcium signals in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3372-3385. [PMID: 35298633 PMCID: PMC9162177 DOI: 10.1093/jxb/erac105] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Calcium acts as a signal and transmits information in all eukaryotes. Encoding machinery consisting of calcium channels, stores, buffers, and pumps can generate a variety of calcium transients in response to external stimuli, thus shaping the calcium signature. Mechanisms for the transmission of calcium signals have been described, and a large repertoire of calcium binding proteins exist that can decode calcium signatures into specific responses. Whilst straightforward as a concept, mysteries remain as to exactly how such information processing is biochemically implemented. Novel developments in imaging technology and genetically encoded sensors (such as calcium indicators), in particular for multi-signal detection, are delivering exciting new insights into intra- and intercellular calcium signaling. Here, we review recent advances in characterizing the encoding, transmission, and decoding mechanisms, with a focus on long-distance calcium signaling. We present technological advances and computational frameworks for studying the specificity of calcium signaling, highlight current gaps in our understanding and propose techniques and approaches for unravelling the underlying mechanisms.
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Affiliation(s)
- Claudia Allan
- University of Canterbury, School of Biological Science, Christchurch, New Zealand
| | - Richard J Morris
- Computational and Systems Biology, John Innes Centre, Norwich, UK
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5
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Çetinbaş-Genç A, Conti V, Cai G. Let's shape again: the concerted molecular action that builds the pollen tube. PLANT REPRODUCTION 2022; 35:77-103. [PMID: 35041045 DOI: 10.1007/s00497-022-00437-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The pollen tube is being subjected to control by a complex network of communication that regulates its shape and the misfunction of a single component causes specific deformations. In flowering plants, the pollen tube is a tubular extension of the pollen grain required for successful sexual reproduction. Indeed, maintaining the unique shape of the pollen tube is essential for the pollen tube to approach the embryo sac. Many processes and molecules (such as GTPase activity, phosphoinositides, Ca2+ gradient, distribution of reactive oxygen species and nitric oxide, nonuniform pH values, organization of the cytoskeleton, balance between exocytosis and endocytosis, and cell wall structure) play key and coordinated roles in maintaining the cylindrical shape of pollen tubes. In addition, the above factors must also interact with each other so that the cell shape is maintained while the pollen tube follows chemical signals in the pistil that guide it to the embryo sac. Any intrinsic changes (such as erroneous signals) or extrinsic changes (such as environmental stresses) can affect the above factors and thus fertilization by altering the tube morphology. In this review, the processes and molecules that enable the development and maintenance of the unique shape of pollen tubes in angiosperms are presented emphasizing their interaction with specific tube shape. Thus, the purpose of the review is to investigate whether specific deformations in pollen tubes can help us to better understand the mechanism underlying pollen tube shape.
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Affiliation(s)
- Aslıhan Çetinbaş-Genç
- Department of Biology, Marmara University, Göztepe Campus, 34722, Kadıköy, Istanbul, Turkey.
| | - Veronica Conti
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
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6
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Wasąg P, Suwińska A, Lenartowska M, Lenartowski R. RNAi-Mediated Knockdown of Calreticulin3a Impairs Pollen Tube Growth in Petunia. Int J Mol Sci 2022; 23:ijms23094987. [PMID: 35563382 PMCID: PMC9103332 DOI: 10.3390/ijms23094987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/14/2022] [Accepted: 04/26/2022] [Indexed: 02/05/2023] Open
Abstract
Pollen tube growth depends on several complex processes, including exo/endocytosis, cell wall biogenesis, intracellular transport, and cell signaling. Our previous results provided evidence that calreticulin (CRT)—a prominent calcium (Ca2+)-buffering molecular chaperone in the endoplasmic reticulum (ER) lumen—is involved in pollen tube formation and function. We previously cloned and characterized the CRT gene belonging to the CRT1/2 subgroup from Petunia hybrida (PhCRT1/2), and found that post-transcriptional silencing of PhCRT1/2 expression strongly impaired pollen tube growth in vitro. Here, we report cloning of a new PhCRT3a homolog; we identified the full-length cDNA sequence and described its molecular characteristics and phylogenetic relationships to other plant CRT3 genes. Using an RNA interference (RNAi) strategy, we found that knockdown of PhCRT3a gene expression caused numerous defects in the morphology and ultrastructure of cultivated pollen tubes, including disorganization of the actin cytoskeleton and loss of cytoplasmic zonation. Elongation of siPhCRT3a pollen tubes was disrupted, and some of them ruptured. Our present data provide the first evidence that PhCRT3a expression is required for normal pollen tube growth. Thus, we discuss relationships between diverse CRT isoforms in several interdependent processes driving the apical growth of the pollen tube, including actomyosin-dependent cytoplasmic streaming, organelle positioning, vesicle trafficking, and cell wall biogenesis.
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Affiliation(s)
- Piotr Wasąg
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland; (P.W.); (A.S.); (M.L.)
- Department of Biochemistry and Cell Biology, Faculty of Biological Sciences, Kazimierz Wielki University, 85-093 Bydgoszcz, Poland
| | - Anna Suwińska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland; (P.W.); (A.S.); (M.L.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland; (P.W.); (A.S.); (M.L.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland
| | - Robert Lenartowski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland; (P.W.); (A.S.); (M.L.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland
- Correspondence:
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7
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Do Plasmodesmata Play a Prominent Role in Regulation of Auxin-Dependent Genes at Early Stages of Embryogenesis? Cells 2021; 10:cells10040733. [PMID: 33810252 PMCID: PMC8066550 DOI: 10.3390/cells10040733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 01/24/2023] Open
Abstract
Plasmodesmata form intercellular channels which ensure the transport of various molecules during embryogenesis and postembryonic growth. However, high permeability of plasmodesmata may interfere with the establishment of auxin maxima, which are required for cellular patterning and the development of distinct tissues. Therefore, diffusion through plasmodesmata is not always desirable and the symplastic continuum must be broken up to induce or accomplish some developmental processes. Many data show the role of auxin maxima in the regulation of auxin-responsive genes and the establishment of various cellular patterns. However, still little is known whether and how these maxima are formed in the embryo proper before 16-cell stage, that is, when there is still a nonpolar distribution of auxin efflux carriers. In this work, we focused on auxin-dependent regulation of plasmodesmata function, which may provide rapid and transient changes of their permeability, and thus take part in the regulation of gene expression.
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8
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Andrews C, Xu Y, Kirberger M, Yang JJ. Structural Aspects and Prediction of Calmodulin-Binding Proteins. Int J Mol Sci 2020; 22:ijms22010308. [PMID: 33396740 PMCID: PMC7795363 DOI: 10.3390/ijms22010308] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 11/19/2022] Open
Abstract
Calmodulin (CaM) is an important intracellular protein that binds Ca2+ and functions as a critical second messenger involved in numerous biological activities through extensive interactions with proteins and peptides. CaM’s ability to adapt to binding targets with different structures is related to the flexible central helix separating the N- and C-terminal lobes, which allows for conformational changes between extended and collapsed forms of the protein. CaM-binding targets are most often identified using prediction algorithms that utilize sequence and structural data to predict regions of peptides and proteins that can interact with CaM. In this review, we provide an overview of different CaM-binding proteins, the motifs through which they interact with CaM, and shared properties that make them good binding partners for CaM. Additionally, we discuss the historical and current methods for predicting CaM binding, and the similarities and differences between these methods and their relative success at prediction. As new CaM-binding proteins are identified and classified, we will gain a broader understanding of the biological processes regulated through changes in Ca2+ concentration through interactions with CaM.
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Affiliation(s)
- Corey Andrews
- Center for Diagnostics and Therapeutics, Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; (C.A.); (Y.X.)
| | - Yiting Xu
- Center for Diagnostics and Therapeutics, Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; (C.A.); (Y.X.)
| | - Michael Kirberger
- Chemistry Division, Georgia Gwinnett College, Lawrenceville, GA 30043, USA;
| | - Jenny J. Yang
- Center for Diagnostics and Therapeutics, Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; (C.A.); (Y.X.)
- Correspondence: ; Tel.: +1-4044135520
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9
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Duan Z, Ito K, Tominaga M. Heterologous transformation of Camelina sativa with high-speed chimeric myosin XI-2 promotes plant growth and leads to increased seed yield. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2020; 37:253-259. [PMID: 33088188 PMCID: PMC7557661 DOI: 10.5511/plantbiotechnology.20.0225b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/25/2020] [Indexed: 06/11/2023]
Abstract
Camelina sativa is a Brassicaceae oilseed plant used as a biotechnology platform for biofuel and healthy vegetable oil. As Camelina is closely related to the model plant Arabidopsis, the genetic tools of Arabidopsis are considered useful when applied to Camelina. Myosin XI-2 is one of the major motive forces driving cytoplasmic streaming in Arabidopsis. In our previous study, high-speed chimeric myosin XI-2, a myosin XI-2 artificially modified by genetically exchanging the motor domain of Arabidopsis myosin XI-2 with the faster Chara myosin XI, was shown to accelerate cytoplasmic streaming and promote plant growth in Arabidopsis. Here, we heterologously transformed this high-speed Chara-Arabidopsis chimeric myosin XI-2 gene in Camelina. The transgenic plants exhibited not only enhancement of leaf development and main stem elongation but also early flowering and seed setting, indicating that the high-speed chimeric myosin XI-2 can improve plant growth in Camelina. Interestingly, total seed yield was significantly increased in the transgenic plants as the total seed number increased. Our results suggest that the high-speed myosin XI system might also be effective to improve the growth of other closely related plant species.
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Affiliation(s)
- Zhongrui Duan
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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10
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Tan YQ, Yang Y, Zhang A, Fei CF, Gu LL, Sun SJ, Xu W, Wang L, Liu H, Wang YF. Three CNGC Family Members, CNGC5, CNGC6, and CNGC9, Are Required for Constitutive Growth of Arabidopsis Root Hairs as Ca 2+-Permeable Channels. PLANT COMMUNICATIONS 2020; 1:100001. [PMID: 33404548 PMCID: PMC7748020 DOI: 10.1016/j.xplc.2019.100001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/06/2019] [Accepted: 08/23/2019] [Indexed: 05/03/2023]
Abstract
The genetic identities of Ca2+ channels in root hair (RH) tips essential for constitutive RH growth have remained elusive for decades. Here, we report the identification and characterization of three cyclic nucleotide-gated channel (CNGC) family members, CNGC5, CNGC6, and CNGC9, as Ca2+ channels essential for constitutive RH growth in Arabidopsis. We found that the cngc5-1cngc6-2cngc9-1 triple mutant (designated shrh1) showed significantly shorter and branching RH phenotypes as compared with the wild type. The defective RH growth phenotype of shrh1 could be rescued by either the expression of CNGC5, CNGC6, or CNGC9 single gene or by the supply of high external Ca2+, but could not be rescued by external K+ supply. Cytosolic Ca2+ imaging and patch-clamp data in HEK293T cells showed that these three CNGCs all function as Ca2+-permeable channels. Cytosolic Ca2+ imaging in growing RHs further showed that the Ca2+ gradients and their oscillation in RH tips were dramatically attenuated in shrh1 compared with those in the wild type. Phenotypic analysis revealed that these three CNGCs are Ca2+ channels essential for constitutive RH growth, with different roles in RHs from the conditional player CNGC14. Moreover, we found that these three CNGCs are involved in auxin signaling in RHs. Taken together, our study identified CNGC5, CNGC6, and CNGC9 as three key Ca2+ channels essential for constitutive RH growth and auxin signaling in Arabidopsis.
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Affiliation(s)
- Yan-Qiu Tan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang Yang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - An Zhang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Cui-Fang Fei
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Li-Li Gu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Shu-Jing Sun
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Wei Xu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Lingling Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yong-Fei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Corresponding author
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11
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York-Andersen AH, Hu Q, Wood BW, Wolfner MF, Weil TT. A calcium-mediated actin redistribution at egg activation in Drosophila. Mol Reprod Dev 2019; 87:293-304. [PMID: 31880382 PMCID: PMC7044060 DOI: 10.1002/mrd.23311] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 12/12/2019] [Indexed: 12/24/2022]
Abstract
Egg activation is the essential process in which mature oocytes gain the competency to proceed into embryonic development. Many events of egg activation are conserved, including an initial rise of intracellular calcium. In some species, such as echinoderms and mammals, changes in the actin cytoskeleton occur around the time of fertilization and egg activation. However, the interplay between calcium and actin during egg activation remains unclear. Here, we use imaging, genetics, pharmacological treatment, and physical manipulation to elucidate the relationship between calcium and actin in living Drosophila eggs. We show that, before egg activation, actin is smoothly distributed between ridges in the cortex of the dehydrated mature oocytes. At the onset of egg activation, we observe actin spreading out as the egg swells though the intake of fluid. We show that a relaxed actin cytoskeleton is required for the intracellular rise of calcium to initiate and propagate. Once the swelling is complete and the calcium wave is traversing the egg, it leads to a reorganization of actin in a wavelike manner. After the calcium wave, the actin cytoskeleton has an even distribution of foci at the cortex. Together, our data show that calcium resets the actin cytoskeleton at egg activation, a model that we propose to be likely conserved in other species.
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Affiliation(s)
| | - Qinan Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | - Benjamin W Wood
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Mariana F Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| | - Timothy T Weil
- Department of Zoology, University of Cambridge, Cambridge, UK
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12
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Sparkes I. Lessons from optical tweezers: quantifying organelle interactions, dynamics and modelling subcellular events. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:55-61. [PMID: 30081386 DOI: 10.1016/j.pbi.2018.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/06/2018] [Accepted: 07/13/2018] [Indexed: 05/24/2023]
Abstract
Optical tweezers enable users to physically trap organelles and move them laterally within the plant cell. Recent advances have highlighted physical interactions between functionally related organelle pairs, such as ER-Golgi and peroxisome-chloroplast, and have shown how organelle positioning affects plant growth. Quantification of these processes has provided insight into the force components which ultimately drive organelle movement and positioning in plant cells. Application of optical tweezers has therefore revolutionised our understanding of plant organelle dynamics.
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Affiliation(s)
- Imogen Sparkes
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
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13
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Haraguchi T, Ito K, Duan Z, Rula S, Takahashi K, Shibuya Y, Hagino N, Miyatake Y, Nakano A, Tominaga M. Functional Diversity of Class XI Myosins in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2018; 59:2268-2277. [PMID: 30398666 PMCID: PMC6217714 DOI: 10.1093/pcp/pcy147] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 07/20/2018] [Indexed: 05/24/2023]
Abstract
Plant myosin XI acts as a motive force for cytoplasmic streaming through interacting with actin filaments within the cell. Arabidopsis thaliana (At) has 13 genes belonging to the myosin XI family. Previous reverse genetic approaches suggest that At myosin XIs are partially redundant, but are functionally diverse for their specific tasks within the plant. However, the tissue-specific expression and enzymatic properties of myosin XIs have to date been poorly understood, primarily because of the difficulty in cloning and expressing large myosin XI genes and proteins. In this study, we cloned full-length cDNAs and promoter regions for all 13 At myosin XIs and identified tissue-specific expression (using promoter-reporter assays) and motile and enzymatic activities (using in vitro assays). In general, myosins belonging to the same class have similar velocities and ATPase activities. However, the velocities and ATPase activities of the 13 At myosin XIs are significantly different and are classified broadly into three groups based on velocity (high group, medium group and low group). Interestingly, the velocity groups appear roughly correlated with the tissue-specific expression patterns. Generally, ubiquitously expressed At myosin XIs belong to the medium-velocity group, pollen-specific At myosin XIs belong to the high-velocity group and only one At myosin XI (XI-I) is classified as belonging to the low-velocity group. In this study, we demonstrated the diversity of the 13 myosin XIs in Arabidopsis at the molecular and tissue levels. Our results indicate that myosin XIs in higher plants have distinct motile and enzymatic activities adapted for their specific roles.
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Affiliation(s)
- Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, Japan
| | - Zhongrui Duan
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
| | - Sa Rula
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, Japan
| | - Kento Takahashi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, Japan
| | - Yuno Shibuya
- Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
| | - Nanako Hagino
- Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
| | - Yuko Miyatake
- Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Live Cell Super-Resolution Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, Wako, Saitama, Japan
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
- Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, Japan
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14
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Lipchinsky A. Electromechanics of polarized cell growth. Biosystems 2018; 173:114-132. [PMID: 30300677 DOI: 10.1016/j.biosystems.2018.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/30/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
Abstract
One of the most challenging questions in cell and developmental biology is how molecular signals are translated into mechanical forces that ultimately drive cell growth and motility. Despite an impressive body of literature demonstrating the importance of cytoskeletal and motor proteins as well as osmotic stresses for cell developmental mechanics, a host of dissenting evidence strongly suggests that these factors per se cannot explain growth mechanics even at the level of a single tip-growing cell. The present study addresses this issue by exploring fundamental interrelations between electrical and mechanical fields operating in cells. In the first instance, we employ a simplified but instructive model of a quiescent cell to demonstrate that even in a quasi-equilibrium state, ion transport processes are conditioned principally by mechanical tenets. Then we inquire into the electromechanical conjugacy in growing pollen tubes as biologically relevant and physically tractable developmental systems owing to their extensively characterized growth-associated ionic fluxes and strikingly polarized growth and morphology. A comprehensive analysis of the multifold stress pattern in the growing apices of pollen tubes suggests that tip-focused ionic fluxes passing through the polyelectrolyte-rich apical cytoplasm give rise to electrokinetic flows that actualize otherwise isotropic intracellular turgor into anisotropic stress field. The stress anisotropy can be then imparted from the apical cytoplasm to the abutting frontal cell wall to induce its local extension and directional cell growth. Converging lines of evidence explored in the concluding sections attest that tip-focused ionic fluxes and associated interfacial transport phenomena are not specific for pollen tubes but are also employed by a vast variety of algal, plant, fungal and animal cells, rendering their cytoplasmic stress fields essentially anisotropic and ultimately instrumental in cell shaping, growth and motility.
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Affiliation(s)
- Andrei Lipchinsky
- Department of Plant Physiology and Biochemistry, St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russia.
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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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Rula S, Suwa T, Kijima ST, Haraguchi T, Wakatsuki S, Sato N, Duan Z, Tominaga M, Uyeda TQP, Ito K. Measurement of enzymatic and motile activities of Arabidopsis myosins by using Arabidopsis actins. Biochem Biophys Res Commun 2017; 495:2145-2151. [PMID: 29248727 DOI: 10.1016/j.bbrc.2017.12.071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 11/16/2022]
Abstract
There are two classes of myosin, XI and VIII, in higher plants. Myosin XI moves actin filaments at high speed and its enzyme activity is also very high. In contrast, myosin VIII moves actin filaments very slowly with very low enzyme activity. Because most of these enzymatic and motile activities were measured using animal skeletal muscle α-actin, but not plant actin, they would not accurately reflect the actual activities in plant cells. We thus measured enzymatic and motile activities of the motor domains of two Arabidopsis myosin XI isoforms (MYA2, XI-B), and one Arabidopsis myosin VIII isoform (ATM1), by using three Arabidopsis actin isoforms (ACT1, ACT2, and ACT7). The measured activities were different from those measured by using muscle actin. Moreover, Arabidopsis myosins showed different enzymatic and motile activities when using different Arabidopsis actin isoforms. Our results suggest that plant actin should be used for measuring enzymatic and motile activities of plant myosins and that different actin isoforms in plant cells might function as different tracks along which affinities and velocities of each myosin isoform are modulated.
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Affiliation(s)
- Sa Rula
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Takahiro Suwa
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Saku T Kijima
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8565, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
| | - Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Shinryu Wakatsuki
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Naruki Sato
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Zhongrui Duan
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan; Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Taro Q P Uyeda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8565, Japan; Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan.
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17
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Bogaert KA, Beeckman T, De Clerck O. Egg activation-triggered shape change in the Dictyota dichotoma (Phaeophyceae) zygote is actin-myosin and secretion dependent. ANNALS OF BOTANY 2017; 120:529-538. [PMID: 28961769 PMCID: PMC5737549 DOI: 10.1093/aob/mcx085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/07/2017] [Indexed: 06/07/2023]
Abstract
Background and Aims Cellular morphogenesis in land plants and brown algae is typically a slow process involving growth established by an interplay of turgor pressure and cell wall rigidity. However, a recent study showed that zygotes of the brown alga Dictyota dichotoma undergo a rapid shape change from a sphere to an elongated spheroid in about 90 s, establishing the first body axis. Methods Using a combination of pharmacology, staining techniques, membrane depolarization and microscopy techniques (brightfield, transmission electron microscopy and confocal laser scanning microscopy), egg activation and the shape change of the egg cell of D. dichotoma was studied. Key Results It was established that elongation of the zygote does not involve growth, i.e. a positive change in size. The elongation is dependent on F-actin and myosin but independent of microtubules. Secretion was also found to be necessary for elongation after addition of brefeldin A. Moreover, a temporal correlation between extracellular matrix secretion and elongation was observed. Ionomycin and high potassium seawater are capable of triggering the onset of elongation, suggesting a role for membrane depolarization and calcium influx in the signalling mechanism. The elongated cells are shorter in the presence of ionomycin, suggesting a role for calcium in elongation. Conclusions A model is proposed in which the fast elongation of the fertilized egg in Dictyota is accomplished by a force generated by F-actin and myosin, regulated by cytoplasmic calcium concentrations and by secretion during elongation lowering the antagonistic force. The finding of early extracellular matrix secretion, membrane depolarization and ionophore-triggered egg activation suggest significant differences in the mechanism of egg activation signalling between D. dichotoma and the oogamous brown algal model system Fucus .
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Affiliation(s)
- Kenny A Bogaert
- Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
| | - Tom Beeckman
- VIB-UGent Center for Plant Systems Biology, Technologiepark 927, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Olivier De Clerck
- Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
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18
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Suwińska A, Wasąg P, Zakrzewski P, Lenartowska M, Lenartowski R. Calreticulin is required for calcium homeostasis and proper pollen tube tip growth in Petunia. PLANTA 2017; 245:909-926. [PMID: 28078426 PMCID: PMC5391374 DOI: 10.1007/s00425-017-2649-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/05/2017] [Indexed: 05/19/2023]
Abstract
MAIN CONCLUSION Calreticulin is involved in stabilization of the tip-focused Ca 2+ gradient and the actin cytoskeleton arrangement and function that is required for several key processes driving Petunia pollen tube tip growth. Although the precise mechanism is unclear, stabilization of a tip-focused calcium (Ca2+) gradient seems to be critical for pollen germination and pollen tube growth. We hypothesize that calreticulin (CRT), a Ca2+-binding/buffering chaperone typically residing in the lumen of the endoplasmic reticulum (ER) of eukaryotic cells, is an excellent candidate to fulfill this role. We previously showed that in Petunia pollen tubes growing in vitro, CRT is translated on ER membrane-bound ribosomes that are abundant in the subapical zone of the tube, where CRT's Ca2+-buffering and chaperone activities might be particularly required. Here, we sought to determine the function of CRT using small interfering RNA (siRNA) to, for the first time in pollen tubes growing in vitro, knockdown expression of a gene. We demonstrate that siRNA-mediated post-transcriptional silencing of Petunia hybrida CRT gene (PhCRT) expression strongly impairs pollen tube growth, cytoplasmic zonation, actin cytoskeleton organization, and the tip-focused Ca2+ gradient. Moreover, reduction of CRT alters the localization and disturbs the structure of the ER in abnormally elongating pollen tubes. Finally, cytoplasmic streaming is inhibited, and most of the pollen tubes rupture. Our data clearly show an interplay between CRT, Ca2+ gradient, actin-dependent cytoplasmic streaming, organelle positioning, and vesicle trafficking during pollen tube elongation. Thus, we suggest that CRT functions in Petunia pollen tube growth by stabilizing Ca2+ homeostasis and acting as a chaperone to assure quality control of glycoproteins passing through the ER.
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Affiliation(s)
- Anna Suwińska
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Piotr Wasąg
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Przemysław Zakrzewski
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Marta Lenartowska
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland.
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19
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Michard E, Simon AA, Tavares B, Wudick MM, Feijó JA. Signaling with Ions: The Keystone for Apical Cell Growth and Morphogenesis in Pollen Tubes. PLANT PHYSIOLOGY 2017; 173:91-111. [PMID: 27895207 PMCID: PMC5210754 DOI: 10.1104/pp.16.01561] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/19/2016] [Indexed: 05/18/2023]
Abstract
Ion homeostasis and signaling are crucial to regulate pollen tube growth and morphogenesis and affect upstream membrane transporters and downstream targets.
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Affiliation(s)
- Erwan Michard
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Alexander A Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Bárbara Tavares
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Michael M Wudick
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
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20
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Geitmann A, Nebenführ A. Navigating the plant cell: intracellular transport logistics in the green kingdom. Mol Biol Cell 2016; 26:3373-8. [PMID: 26416952 PMCID: PMC4591683 DOI: 10.1091/mbc.e14-10-1482] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Intracellular transport in plant cells occurs on microtubular and actin arrays. Cytoplasmic streaming, the rapid motion of plant cell organelles, is mostly driven by an actin–myosin mechanism, whereas specialized functions, such as the transport of large cargo or the assembly of a new cell wall during cell division, are performed by the microtubules. Different modes of transport are used, fast and slow, to either haul cargo over long distances or ascertain high-precision targeting, respectively. Various forms of the actin-specific motor protein myosin XI exist in plant cells and might be involved in different cellular functions.
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Affiliation(s)
- Anja Geitmann
- Department of Biological Sciences, Institut de recherche en biologie végétale, University of Montreal, Montreal, QC H1X 2B2, Canada
| | - Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840
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21
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Haraguchi T, Tominaga M, Nakano A, Yamamoto K, Ito K. Myosin XI-I is Mechanically and Enzymatically Unique Among Class-XI Myosins in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:1732-1743. [PMID: 27273580 DOI: 10.1093/pcp/pcw097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/03/2016] [Indexed: 06/06/2023]
Abstract
Arabidopsis possesses 13 genes encoding class-XI myosins. Among these, myosin XI-I is phylogenetically distant. To examine the molecular properties of Arabidopsis thaliana myosin XI-I (At myosin XI-I), we performed in vitro mechanical and enzymatic analyses using recombinant constructs of At myosin XI-I. Unlike other biochemically studied class-XI myosins, At myosin XI-I showed extremely low actin-activated ATPase activity (Vmax = 3.7 Pi s(-1) head(-1)). The actin-sliding velocity of At myosin XI-I was 0.25 µm s(-1), >10 times lower than those of other class-XI myosins. The ADP dissociation rate from acto-At myosin XI-I was 17 s(-1), accounting for the low actin-sliding velocity. In contrast, the apparent affinity for actin in the presence of ATP, estimated from Kapp (0.61 µM) of actin-activated ATPase, was extremely high. The equilibrium dissociation constant for actin was very low in both the presence and absence of ATP, indicating a high affinity for actin. To examine At myosin XI-I motility in vivo, green fluorescent protein-fused full-length At myosin XI-I was expressed in cultured Arabidopsis cells. At myosin XI-I localized not only on the nuclear envelope but also on small dots moving slowly (0.23 µm s(-1)) along actin filaments. Our results show that the properties of At myosin XI-I differ from those of other Arabidopsis class-XI myosins. The data suggest that At myosin XI-I does not function as a driving force for cytoplasmic streaming but regulates the organelle velocity, supports processive organelle movement or acts as a tension generator.
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Affiliation(s)
- Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, 263-8522 Japan These authors contributed equally to this work.
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan These authors contributed equally to this work.
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, Wako, Saitama, 351-0198 Japan Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Keiichi Yamamoto
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, 263-8522 Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba, 263-8522 Japan
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22
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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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23
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Madison SL, Buchanan ML, Glass JD, McClain TF, Park E, Nebenführ A. Class XI Myosins Move Specific Organelles in Pollen Tubes and Are Required for Normal Fertility and Pollen Tube Growth in Arabidopsis. PLANT PHYSIOLOGY 2015; 169:1946-60. [PMID: 26358416 PMCID: PMC4634091 DOI: 10.1104/pp.15.01161] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
Pollen tube growth is an essential aspect of plant reproduction because it is the mechanism through which nonmotile sperm cells are delivered to ovules, thus allowing fertilization to occur. A pollen tube is a single cell that only grows at the tip, and this tip growth has been shown to depend on actin filaments. It is generally assumed that myosin-driven movements along these actin filaments are required to sustain the high growth rates of pollen tubes. We tested this conjecture by examining seed set, pollen fitness, and pollen tube growth for knockout mutants of five of the six myosin XI genes expressed in pollen of Arabidopsis (Arabidopsis thaliana). Single mutants had little or no reduction in overall fertility, whereas double mutants of highly similar pollen myosins had greater defects in pollen tube growth. In particular, myo11c1 myo11c2 pollen tubes grew more slowly than wild-type pollen tubes, which resulted in reduced fitness compared with the wild type and a drastic reduction in seed set. Golgi stack and peroxisome movements were also significantly reduced, and actin filaments were less organized in myo11c1 myo11c2 pollen tubes. Interestingly, the movement of yellow fluorescent protein-RabA4d-labeled vesicles and their accumulation at pollen tube tips were not affected in the myo11c1 myo11c2 double mutant, demonstrating functional specialization among myosin isoforms. We conclude that class XI myosins are required for organelle motility, actin organization, and optimal growth of pollen tubes.
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Affiliation(s)
- Stephanie L Madison
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
| | - Matthew L Buchanan
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
| | - Jeremiah D Glass
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
| | - Tarah F McClain
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
| | - Eunsook Park
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
| | - Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
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24
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Tominaga M, Ito K. The molecular mechanism and physiological role of cytoplasmic streaming. CURRENT OPINION IN PLANT BIOLOGY 2015; 27:104-110. [PMID: 26202096 DOI: 10.1016/j.pbi.2015.06.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 05/20/2023]
Abstract
Cytoplasmic streaming occurs widely in plants ranging from algae to angiosperms. However, the molecular mechanism and physiological role of cytoplasmic streaming have long remained unelucidated. Recent molecular genetic approaches have identified specific myosin members (XI-2 and XI-K as major and XI-1, XI-B, and XI-I as minor motive forces) for the generation of cytoplasmic streaming among 13 myosin XIs in Arabidopsis thaliana. Simultaneous knockout of these myosin XI members led to a reduced velocity of cytoplasmic streaming and marked defects of plant development. Furthermore, the artificial modifications of myosin XI-2 velocity changed plant and cell sizes along with the velocity of cytoplasmic streaming. Therefore, we assume that cytoplasmic streaming is one of the key regulators in determining plant size.
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Affiliation(s)
- Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan.
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
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25
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Hepler PK, Winship LJ. The pollen tube clear zone: clues to the mechanism of polarized growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:79-92. [PMID: 25431342 DOI: 10.1111/jipb.12315] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/24/2014] [Indexed: 05/08/2023]
Abstract
Pollen tubes usually exhibit a prominent region at their apex called the "clear zone" because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen tubes, and thus serves as an indicator of pollen tube health. Nevertheless we do not understand how it arises or how it is maintained. Here we review the structure of the clear zone, and attempt to explain the factors that contribute to its formation. While amyloplasts and vacuolar elements are excluded from the clear zone, virtually all other organelles are present including secretory vesicles, mitochondria, Golgi dictyosomes, and the endoplasmic reticulum (ER). Secretory vesicles aggregate into an inverted cone appressed against the apical plasma membrane. ER elements move nearly to the extreme apex, whereas mitochondria and Golgi dictyosomes move less far forward. The cortical actin fringe assumes a central position in the control of clear zone formation and maintenance, given its role in generating cytoplasmic streaming. Other likely factors include the tip-focused calcium gradient, the apical pH gradient, the influx of water, and a host of signaling factors (small G-proteins). We think that the clear zone is an emergent property that depends on the interaction of several factors crucial for polarized growth.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts, 01003, USA
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Cai G, Parrotta L, Cresti M. Organelle trafficking, the cytoskeleton, and pollen tube growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:63-78. [PMID: 25263392 DOI: 10.1111/jipb.12289] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 06/03/2023]
Abstract
The pollen tube is fundamental for the reproduction of seed plants. Characteristically, it grows relatively quickly and uni-directionally ("polarized growth") to extend the male gametophyte to reach the female gametophyte. The pollen tube forms a channel through which the sperm cells move so that they can reach their targets in the ovule. To grow quickly and directionally, the pollen tube requires an intense movement of organelles and vesicles that allows the cell's contents to be distributed to sustain the growth rate. While the various organelles distribute more or less uniformly within the pollen tube, Golgi-released secretory vesicles accumulate massively at the pollen tube apex, that is, the growing region. This intense movement of organelles and vesicles is dependent on the dynamics of the cytoskeleton, which reorganizes differentially in response to external signals and coordinates membrane trafficking with the growth rate of pollen tubes.
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Affiliation(s)
- Giampiero Cai
- Department of Life Sciences, University of Siena, Siena, 53100, Italy
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27
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Diensthuber RP, Tominaga M, Preller M, Hartmann FK, Orii H, Chizhov I, Oiwa K, Tsiavaliaris G. Kinetic mechanism of Nicotiana tabacum myosin-11 defines a new type of a processive motor. FASEB J 2015; 29:81-94. [PMID: 25326536 DOI: 10.1096/fj.14-254763] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The 175-kDa myosin-11 from Nicotiana tabacum (Nt(175kDa)myosin-11) is exceptional in its mechanical activity as it is the fastest known processive actin-based motor, moving 10 times faster than the structurally related class 5 myosins. Although this ability might be essential for long-range organelle transport within larger plant cells, the kinetic features underlying the fast processive movement of Nt(175kDa)myosin-11 still remain unexplored. To address this, we generated a single-headed motor domain construct and carried out a detailed kinetic analysis. The data demonstrate that Nt(175kDa)myosin-11 is a high duty ratio motor, which remains associated with actin most of its enzymatic cycle. However, different from other processive myosins that establish a high duty ratio on the basis of a rate-limiting ADP-release step, Nt(175kDa)myosin-11 achieves a high duty ratio by a prolonged duration of the ATP-induced isomerization of the actin-bound states and ADP release kinetics, both of which in terms of the corresponding time constants approach the total ATPase cycle time. Molecular modeling predicts that variations in the charge distribution of the actin binding interface might contribute to the thermodynamic fine-tuning of the kinetics of this myosin. Our study unravels a new type of a high duty ratio motor and provides important insights into the molecular mechanism of processive movement of higher plant myosins.
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Affiliation(s)
- Ralph P Diensthuber
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Motoki Tominaga
- Live Cell Molecular Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama, Japan; Science and Technology Agency, PRESTO, Saitama, Japan
| | - Matthias Preller
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany; Centre for Structural Systems Biology, German Electron Synchrotron (DESY), Hamburg, Germany
| | - Falk K Hartmann
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Hidefumi Orii
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan; and
| | - Igor Chizhov
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Kazuhiro Oiwa
- Graduate School of Life Science, University of Hyogo, Hyogo, Japan; and Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), Kobe, Japan
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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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29
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Cytoplasmic streaming velocity as a plant size determinant. Dev Cell 2014; 27:345-52. [PMID: 24229646 DOI: 10.1016/j.devcel.2013.10.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/23/2013] [Accepted: 10/10/2013] [Indexed: 11/21/2022]
Abstract
Cytoplasmic streaming is active transport widely occurring in plant cells ranging from algae to angiosperms. Although it has been revealed that cytoplasmic streaming is generated by organelle-associated myosin XI moving along actin bundles, the fundamental function in plants remains unclear. We generated high- and low-speed chimeric myosin XI by replacing the motor domains of Arabidopsis thaliana myosin XI-2 with those of Chara corallina myosin XI and Homo sapiens myosin Vb, respectively. Surprisingly, the plant sizes of the transgenic Arabidopsis expressing high- and low-speed chimeric myosin XI-2 were larger and smaller, respectively, than that of the wild-type plant. This size change correlated with acceleration and deceleration, respectively, of cytoplasmic streaming. Our results strongly suggest that cytoplasmic streaming is a key determinant of plant size. Furthermore, because cytoplasmic streaming is a common system for intracellular transport in plants, our system could have applications in artificial size control in plants.
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Ketelaar T. The actin cytoskeleton in root hairs: all is fine at the tip. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:749-56. [PMID: 24446547 DOI: 10.1016/j.pbi.2013.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Filamentous actin forms characteristic bundles in plant cells that facilitate cytoplasmic streaming. In contrast, networks of actin exhibiting fast turnover are found especially near sites of rapid cell expansion. These networks may serve various functions including delivering and retaining vesicles while preventing penetration of organelles into the area where cell growth occurs thereby allowing fast turnover of vesicles to and from the plasma membrane. Root hairs elongate by polarized growth at their tips and the local accumulation of fine F-actin near the tip has provided valuable insight into the organization of these networks. Here we will sequentially focus on the role of the actin cytoskeleton in root hair tip growth and on how activities of different actin binding proteins in the apical part of growing root hairs contribute to build the fine F-actin configuration that correlates with tip growth.
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Madison SL, Nebenführ A. Understanding myosin functions in plants: are we there yet? CURRENT OPINION IN PLANT BIOLOGY 2013; 16:710-717. [PMID: 24446546 DOI: 10.1016/j.pbi.2013.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Myosins are motor proteins that drive movements along actin filaments and have long been assumed to be responsible for cytoplasmic streaming in plant cells. This conjecture is now firmly established by genetic analysis in the reference species, Arabidopsis thaliana. This work and similar approaches in the moss, Physcomitrella patens, also established that myosin-driven movements are necessary for cell growth and polarity, organelle distribution and shape, and actin organization and dynamics. Identification of a mechanistic link between intracellular movements and cell expansion has proven more challenging, not the least because of the high level of apparent genetic redundancy among myosin family members. Recent progress in the creation of functional complementation constructs and identification of interaction partners promises a way out of this dilemma.
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Duggal D, Nagwekar J, Rich R, Midde K, Fudala R, Gryczynski I, Borejdo J. Phosphorylation of myosin regulatory light chain has minimal effect on kinetics and distribution of orientations of cross bridges of rabbit skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2013; 306:R222-33. [PMID: 24285364 DOI: 10.1152/ajpregu.00382.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Force production in muscle results from ATP-driven cyclic interactions of myosin with actin. A myosin cross bridge consists of a globular head domain, containing actin and ATP-binding sites, and a neck domain with the associated light chain 1 (LC1) and the regulatory light chain (RLC). The actin polymer serves as a "rail" over which myosin translates. Phosphorylation of the RLC is thought to play a significant role in the regulation of muscle relaxation by increasing the degree of skeletal cross-bridge disorder and increasing muscle ATPase activity. The effect of phosphorylation on skeletal cross-bridge kinetics and the distribution of orientations during steady-state contraction of rabbit muscle is investigated here. Because the kinetics and orientation of an assembly of cross bridges (XBs) can only be studied when an individual XB makes a significant contribution to the overall signal, the number of observed XBs was minimized to ∼20 by limiting the detection volume and concentration of fluorescent XBs. The autofluorescence and photobleaching from an ex vivo sample was reduced by choosing a dye that was excited in the red and observed in the far red. The interference from scattering was eliminated by gating the signal. These techniques decrease large uncertainties associated with determination of the effect of phosphorylation on a few molecules ex vivo with millisecond time resolution. In spite of the remaining uncertainties, we conclude that the state of phosphorylation of RLC had no effect on the rate of dissociation of cross bridges from thin filaments, on the rate of myosin head binding to thin filaments, and on the rate of power stroke. On the other hand, phosphorylation slightly increased the degree of disorder of active cross bridges.
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Affiliation(s)
- Divya Duggal
- Department of Molecular Biology and Immunology and Center for Commercialization of Fluorescence Technologies, University of North Texas, Health Science Center, Fort Worth, Texas
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Tominaga M, Nakano A. Plant-Specific Myosin XI, a Molecular Perspective. FRONTIERS IN PLANT SCIENCE 2012; 3:211. [PMID: 22973289 PMCID: PMC3437519 DOI: 10.3389/fpls.2012.00211] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 08/21/2012] [Indexed: 05/04/2023]
Abstract
In eukaryotic cells, organelle movement, positioning, and communications are critical for maintaining cellular functions and are highly regulated by intracellular trafficking. Directional movement of motor proteins along the cytoskeleton is one of the key regulators of such trafficking. Most plants have developed a unique actin-myosin system for intracellular trafficking. Although the composition of myosin motors in angiosperms is limited to plant-specific myosin classes VIII and XI, there are large families of myosins, especially in class XI, suggesting functional diversification among class XI members. However, the molecular properties and regulation of each myosin XI member remains unclear. To achieve a better understanding of the plant-specific actin-myosin system, the characterization of myosin XI members at the molecular level is essential. In the first half of this review, we summarize the molecular properties of tobacco 175-kDa myosin XI, and in the later half, we focus on myosin XI members in Arabidopsis thaliana. Through detailed comparison of the functional domains of these myosins with the functional domain of myosin V, we look for possible diversification in enzymatic and mechanical properties among myosin XI members concomitant with their regulation.
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Affiliation(s)
- Motoki Tominaga
- Molecular Membrane Biology Laboratory, RIKEN Advanced Science InstituteWako, Saitama, Japan
- Japan Science and Technology Agency, PRESTOKawaguchi, Saitama, Japan
- *Correspondence: Motoki Tominaga, Molecular Membrane Biology Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. e-mail:
| | - Akihiko Nakano
- Molecular Membrane Biology Laboratory, RIKEN Advanced Science InstituteWako, Saitama, Japan
- Department of Biological Sciences, Graduate School of Science, University of TokyoBunkyo-ku, Tokyo, Japan
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