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Symonds K, Teresinski HJ, Hau B, Dwivedi V, Belausov E, Bar-Sinai S, Tominaga M, Haraguchi T, Sadot E, Ito K, Snedden WA. Functional characterization of calmodulin-like proteins, CML13 and CML14, as novel light chains of Arabidopsis class VIII myosins. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2313-2329. [PMID: 38280207 DOI: 10.1093/jxb/erae031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/24/2024] [Indexed: 01/29/2024]
Abstract
Myosins are important motor proteins that associate with the actin cytoskeleton. Structurally, myosins function as heteromeric complexes where smaller light chains, such as calmodulin (CaM), bind to isoleucine-glutamine (IQ) domains in the neck region to facilitate mechano-enzymatic activity. We recently identified Arabidopsis CaM-like (CML) proteins CML13 and CML14 as interactors of proteins containing multiple IQ domains, including a myosin VIII. Here, we demonstrate that CaM, CML13, and CML14 bind the neck region of all four Arabidopsis myosin VIII isoforms. Among CMLs tested for binding to myosins VIIIs, CaM, CML13, and CML14 gave the strongest signals using in planta split-luciferase protein interaction assays. In vitro, recombinant CaM, CML13, and CML14 showed specific, high-affinity, calcium-independent binding to the IQ domains of myosin VIIIs. CaM, CML13, and CML14 co-localized to plasma membrane-bound puncta when co-expressed with red fluorescent protein-myosin fusion proteins containing IQ and tail domains of myosin VIIIs. In vitro actin motility assays using recombinant myosin VIIIs demonstrated that CaM, CML13, and CML14 function as light chains. Suppression of CML13 or CML14 expression using RNA silencing resulted in a shortened-hypocotyl phenotype, similar to that observed in a quadruple myosin mutant, myosin viii4KO. Collectively, our data indicate that Arabidopsis CML13 and CML14 are novel myosin VIII light chains.
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Affiliation(s)
- Kyle Symonds
- Department of Biology, Queen's University, Kingston, ON, Canada
| | | | - Bryan Hau
- Department of Biology, Queen's University, Kingston, ON, Canada
| | - Vikas Dwivedi
- Institute of Plant Sciences, Volcani Institute, ARO, Rishon LeZion 7528809, Israel
| | - Eduard Belausov
- Institute of Plant Sciences, Volcani Institute, ARO, Rishon LeZion 7528809, Israel
| | - Sefi Bar-Sinai
- Institute of Plant Sciences, Volcani Institute, ARO, Rishon LeZion 7528809, Israel
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Einat Sadot
- Institute of Plant Sciences, Volcani Institute, ARO, Rishon LeZion 7528809, Israel
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
| | - Wayne A Snedden
- Department of Biology, Queen's University, Kingston, ON, Canada
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2
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Derksen J, Wilms FHA, Pierson ES. The plant cytoskeleton: its significance in plant development. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/j.1438-8677.1990.tb01441.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- J. Derksen
- Department of Experimental Botany; University of Nijmegen; Toernooiveld NL-6525 ED Nijmegen The Netherlands
| | - F. H. A. Wilms
- Department of Experimental Botany; University of Nijmegen; Toernooiveld NL-6525 ED Nijmegen The Netherlands
| | - E. S. Pierson
- Department of Experimental Botany; University of Nijmegen; Toernooiveld NL-6525 ED Nijmegen The Netherlands
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3
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Intracellular Movements: Integration at the Cellular Level as Reflected in the Organization of Organelle Movements. MECHANICAL INTEGRATION OF PLANT CELLS AND PLANTS 2011. [DOI: 10.1007/978-3-642-19091-9_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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4
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Webster DR, Cooksey KE, Rubin RW. An investigation of the involvement of cytoskeletal structures and secretion in gliding motility of the marine diatom, Amphora coffeaeformis. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/cm.970050204] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Liu AX, Zhang SB, Xu XJ, Ren DT, Liu GQ. Soluble expression and characterization of a GFP-fused pea actin isoform (PEAc1). Cell Res 2004; 14:407-14. [PMID: 15538972 DOI: 10.1038/sj.cr.7290241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A pea actin isoform PEAc1 with green fluorescent protein (GFP) fusion to its C-terminus and His-tag to its N-terminus, was expressed in prokaryotic cells in soluble form, and highly purified with Ni-Chelating Sepharose Fast Flow column. The purified fusion protein (PEAc1-GFP) efficiently inhibited DNase I activities before polymerization, and activated the myosin Mg-ATPase activities after polymerization. The PEAc1-GFP also polymerized into green fluorescent filamentous structures with a critical concentration of 0.75 uM. These filamentous structures were labeled by TRITC-phalloidin, a specific agent for staining actin microfilaments, and identified as having 9 nm diameters by negative staining. These results indicated that PEAc1 preserved the essential characteristics of actin even with His-tag and GFP fusion, suggesting a promising potential to use GFP fusion protein in obtaining soluble plant actin isoform to analyze its physical and biochemical properties in vitro. The PEAc1-GFP was also expressed in tobacco BY2 cells, which offers a new pathway for further studying its distribution and function in vivo.
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Affiliation(s)
- Ai Xiao Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Science, China Agricultural University, Beijing 100094, China.
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Jiang S, Ramachandran S. Identification and Molecular Characterization of Myosin Gene Family in Oryza sativa Genome. ACTA ACUST UNITED AC 2004; 45:590-9. [PMID: 15169941 DOI: 10.1093/pcp/pch061] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myosins play an important role in various developmental processes in plants. We have identified 14 myosin genes in rice (Oryza sativa cv. Nipponbare) genome using sequence information available in public databases. Phylogenetic analysis of these sequences with other plant and non-plant myosins revealed that two of the predicted sequences belonged to class VIII and the others to class XI. All of these genes were distributed on seven chromosomes in the rice genome. Domain searches on these sequences indicated that a typical rice myosin consisted of Myosin_N, head domain, neck (IQ motifs), tail, and dilute (DIL) domain. Based on the sequence information obtained from predicted myosins, we isolated and sequenced two full-length cDNAs, OsMyoVIIIA and OsMyoXIE, representing each of the two classes of myosins. These two cDNAs isolated from different organs existed in isoforms due to differential splicing and showed minor differences from the predicted myosin in exon organization. Out of 14 myosin genes 11 were expressed in three major organs: leaves, panicles, and roots, among which three myosins exhibited different expression levels. On the other hand, three of the total myosin sequences showed organ-specific expression. The existence of different myosin genes and their isoforms in different organs or tissues indicates the diversity of myosin functions in rice.
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Affiliation(s)
- ShuYe Jiang
- Rice Functional Genomics Group, Temasek Life Sciences Laboratory, 1 Research Link, the National University of Singapore, Singapore 117604
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Wang Z, Pesacreta TC. A subclass of myosin XI is associated with mitochondria, plastids, and the molecular chaperone subunit TCP-1? in maize. ACTA ACUST UNITED AC 2004; 57:218-32. [PMID: 14752806 DOI: 10.1002/cm.10168] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The role and regulation of specific plant myosins in cyclosis is not well understood. In the present report, an affinity-purified antibody generated against a conserved tail region of some class XI plant myosin isoforms was used for biochemical and immunofluorescence studies of Zea mays. Myosin XI co-localized with plastids and mitochondria but not with nuclei, the Golgi apparatus, endoplasmic reticulum, or peroxisomes. This suggests that myosin XI is involved in the motility of specific organelles. Myosin XI was more than 50% co-localized with tailless complex polypeptide-1alpha (TCP-1alpha) in tissue sections of mature tissues located more than 1.0 mm from the apex, and the two proteins co-eluted from gel filtration and ion exchange columns. On Western blots, TCP-1alpha isoforms showed a developmental shift from the youngest 5.0 mm of the root to more mature regions that were more than 10.0 mm from the apex. This developmental shift coincided with a higher percentage of myosin XI /TCP-1alpha co-localization, and faster degradation of myosin XI by serine protease. Our results suggest that class XI plant myosin requires TCP-1alpha for regulating folding or providing protection against denaturation.
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Affiliation(s)
- Zhengyuan Wang
- Biology Department, University of Louisiana, Lafayette 70504, USA
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8
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Abstract
Molecular motors that hydrolyze ATP and use the derived energy to generate force are involved in a variety of diverse cellular functions. Genetic, biochemical, and cellular localization data have implicated motors in a variety of functions such as vesicle and organelle transport, cytoskeleton dynamics, morphogenesis, polarized growth, cell movements, spindle formation, chromosome movement, nuclear fusion, and signal transduction. In non-plant systems three families of molecular motors (kinesins, dyneins, and myosins) have been well characterized. These motors use microtubules (in the case of kinesines and dyneins) or actin filaments (in the case of myosins) as tracks to transport cargo materials intracellularly. During the last decade tremendous progress has been made in understanding the structure and function of various motors in animals. These studies are yielding interesting insights into the functions of molecular motors and the origin of different families of motors. Furthermore, the paradigm that motors bind cargo and move along cytoskeletal tracks does not explain the functions of some of the motors. Relatively little is known about the molecular motors and their roles in plants. In recent years, by using biochemical, cell biological, molecular, and genetic approaches a few molecular motors have been isolated and characterized from plants. These studies indicate that some of the motors in plants have novel features and regulatory mechanisms. The role of molecular motors in plant cell division, cell expansion, cytoplasmic streaming, cell-to-cell communication, membrane trafficking, and morphogenesis is beginning to be understood. Analyses of the Arabidopsis genome sequence database (51% of genome) with conserved motor domains of kinesin and myosin families indicates the presence of a large number (about 40) of molecular motors and the functions of many of these motors remain to be discovered. It is likely that many more motors with novel regulatory mechanisms that perform plant-specific functions are yet to be discovered. Although the identification of motors in plants, especially in Arabidopsis, is progressing at a rapid pace because of the ongoing plant genome sequencing projects, only a few plant motors have been characterized in any detail. Elucidation of function and regulation of this multitude of motors in a given species is going to be a challenging and exciting area of research in plant cell biology. Structural features of some plant motors suggest calcium, through calmodulin, is likely to play a key role in regulating the function of both microtubule- and actin-based motors in plants.
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Affiliation(s)
- A S Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins 80523, USA
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Abstract
This first analysis of monocotyledon myosin genes showed that at least five genes, one of which was probably spliced to yield two isoforms, were expressed in maize (Zea mays L.). The complete coding sequence of ZMM1 was determined, as were most of the sequences of two other myosin cDNAs (ZMM2 and ZMM3). ZMM1 and ZMM2 belonged to myosin class XI while ZMM3 was in class VIII. ZMM1 was abundantly expressed in leaves, roots, coleoptiles, and stems. ZMM3 showed a similar distribution but was expressed poorly in pollen. ZMM2 was predominantly expressed in seeds and may be part of a suite of cytoskeletal proteins in reproductive tissues. Phylogenetic analysis suggested that the origin of myosin classes VIII and XI predated that of angiosperms. Immunofluorescence studies using M11L1, a myosin XI antibody specific for the exposed loop 1 head region of myosin, indicated that myosin XI occurred in the cytoplasm of all root tip cells. The highest concentration of myosin XI was in the differentiating epidermal cells. In dividing cells, myosin XI was present near the cytokinetic apparatus at approximately the same concentration seen in other portions of the cytoplasm. Western blot analysis of subcellular fractions indicated that myosin XI was concentrated in mitochondria and low-density membranes.
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Affiliation(s)
- L Liu
- Biological Laboratories, Harvard University, Cambridge, Massachusetts, USA
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Yokota, Yukawa, Muto, Sonobe, Shimmen. Biochemical and immunocytochemical characterization of two types of myosins in cultured tobacco bright yellow-2 cells. PLANT PHYSIOLOGY 1999; 121:525-34. [PMID: 10517844 PMCID: PMC59415 DOI: 10.1104/pp.121.2.525] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/1999] [Accepted: 06/14/1999] [Indexed: 05/21/2023]
Abstract
We have isolated a myosin (referred to as 170-kD myosin) from lily pollen tubes, which consists of 170-kD heavy chain and calmodulin (CaM) light chain and is responsible for cytoplasmic streaming. A 170-kD polypeptide that has similar antigenicity to the 170-kD myosin heavy chain of lily pollen tubes was also present in cultured tobacco (Nicotiana tabacum) Bright Yellow-2 (BY-2) cells, and possessed the ability to interact with F-actin in an ATP-dependent manner. In addition to this myosin, we identified biochemically another kind of myosin in BY-2 cells. This myosin consisted of a CaM light chain and a 175-kD heavy chain with antigenicity different from the 170-kD myosin heavy chain. In the present study, we referred to this myosin as 175-kD myosin. This myosin was able to translocate rhodamine-phalloidin (RP)-labeled F-actin at an average velocity of about 9 &mgr;m/s in the motility assay in vitro. In contrast, the sliding velocity of RP-labeled F-actin translocated by fractions containing the 170-kD myosin was 3 to 4 &mgr;m/s. The velocity of cytoplasmic streaming in living BY-2 cells ranged from 2 to 9 &mgr;m/s. The motile activity of 175-kD myosin in vitro was inhibited by Ca(2+) at concentrations higher than 10(-6) M. Immunoblot analyses using an antiserum against the heavy chain of 170- or 175-kD myosin revealed that in tobacco plants, the 175-kD myosin was expressed in leaf, stem, and root, but not in germinating pollen, while 170-kD myosin was present in all of these plant parts and in germinating pollen. These results suggest that the two types of myosins, 170 and 175 kD, presumably participate in cytoplasmic streaming in BY-2 cells and other somatic cells of tobacco plants.
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Affiliation(s)
- Yokota
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Harima Science Park City, Hyogo 678-12, Japan
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11
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Reichelt S, Knight AE, Hodge TP, Baluska F, Samaj J, Volkmann D, Kendrick-Jones J. Characterization of the unconventional myosin VIII in plant cells and its localization at the post-cytokinetic cell wall. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 19:555-67. [PMID: 10504577 DOI: 10.1046/j.1365-313x.1999.00553.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Myosins are a large superfamily of motor proteins which, in association with actin, are involved in intra- cellular motile processes. In addition to the conventional myosins involved in muscle contractility, there is, in animal cells, a wide range of unconventional myosins implicated in membrane-associated processes, such as vesicle transport and membrane dynamics. In plant cells, however, very little is known about myosins. We have raised an antibody to the recombinant tail region of Arabidopsis thaliana myosin 1 (a class VIII myosin) and used it in immunofluorescence and EM studies on root cells from cress and maize. The plant myosin VIII is found to be concentrated at newly formed cross walls at the stage in which the phragmoplast cytoskeleton has depolymerized and the new cell plate is beginning to mature. These walls are rich in plasmodesmata and we show that they are the regions where the longitudinal actin cables appear to attach. Myosin VIII appears to be localized in these plasmodesmata and we suggest that this protein is involved in maturation of the cell plate and the re-establishment of cytoplasmic actin cables at sites of intercellular communication.
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Affiliation(s)
- S Reichelt
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
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12
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Yokota E, Muto S, Shimmen T. Inhibitory regulation of higher-plant myosin by Ca2+ ions. PLANT PHYSIOLOGY 1999; 119:231-40. [PMID: 9880365 PMCID: PMC32225 DOI: 10.1104/pp.119.1.231] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/1998] [Accepted: 10/03/1998] [Indexed: 05/21/2023]
Abstract
Myosin isolated from the pollen tubes of lily (Lilium longiflorum) is composed of a 170-kD heavy chain (E. Yokota and T. Shimmen [1994] Protoplasma 177: 153-162). Both the motile activity in vitro and the F-actin-stimulated ATPase activity of this myosin were inhibited by Ca2+ at concentrations higher than 10(-6) M. In the Ca2+ range between 10(-6) and 10(-5) M, inhibition of the motile activity was reversible. In contrast, inhibition by more than 10(-5) M Ca2+ was not reversible upon Ca2+ removal. An 18-kD polypeptide that showed the same mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as that of spinach calmodulin (CaM) was present in this myosin fraction. This polypeptide showed a mobility shift in sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a Ca2+-dependent manner. Furthermore, this polypeptide was recognized by antiserum against spinach CaM. By immunoprecipitation using antiserum against the 170-kD heavy chain, the 18-kD polypeptide was coprecipitated with the 170-kD heavy chain, provided that the Ca2+ concentration was low, indicating that this 18-kD polypeptide is bound to the 170-kD myosin heavy chain. However, the 18-kD polypeptide was dissociated from the 170-kD heavy chain at high Ca2+ concentrations, which irreversibly inhibited the motile activity of this myosin. From these results, it is suggested that the 18-kD polypeptide, which is likely to be CaM, is associated with the 170-kD heavy chain as a light chain. It is also suggested that this polypeptide is involved in the regulation of this myosin by Ca2+. This is the first biochemical basis, to our knowledge, for Ca2+ regulation of cytoplasmic streaming in higher plants.
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Affiliation(s)
- E Yokota
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Harima Science Park City, Hyogo 678-12, Japan (E.Y., T.S. )
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13
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Radford JE, White RG. Localization of a myosin-like protein to plasmodesmata. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1998; 14:743-50. [PMID: 9681037 DOI: 10.1046/j.1365-313x.1998.00162.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Myosin has been localized to plasmodesmata in root tissues of Allium cepa, Zea mays and Hordeum vulgare using a polyclonal antibody to animal myosin in both fluorescence and electron microscopy. Labelling was also observed throughout the cytoplasm, mainly associated with the endoplasmic reticulum and plasma membrane. On Western blots, bands of 180 and 110 kDa were consistently labelled in all three species. These bands were also labelled when the blot was incubated in actin prior to staining with antibodies to actin, raising the possibility that either of these proteins (180 kDa or 110 kDa) may be present in plasmodesmata. Pre-treatment of the tissue with 2,3-butanedione monoxime (BDM), an inhibitor of actin-myosin motility, resulted in a strong constriction of the neck region of plasmodesmata. These results indicate that a myosin-like protein may be present in plasmodesmata and may also play a role in the regulation of transport at the neck region.
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Affiliation(s)
- J E Radford
- Department of Biological Sciences, Monash University, Clayton, Victoria, Australia.
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14
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Ren D, Han S, Yan L. Actin and myosin during pollen germination. CHINESE SCIENCE BULLETIN-CHINESE 1998. [DOI: 10.1007/bf02883579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Li YQ, Moscatelli A, Cai G, Cresti M. Functional interactions among cytoskeleton, membranes, and cell wall in the pollen tube of flowering plants. INTERNATIONAL REVIEW OF CYTOLOGY 1997; 176:133-99. [PMID: 9394919 DOI: 10.1016/s0074-7696(08)61610-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pollen tube is a cellular system that plays a fundamental role during the process of fertilization in higher plants. Because it is so important, the pollen tube has been subjected to intensive studies with the aim of understanding its biology. The pollen tube represents a fascinating model for studying interactions between the internal cytoskeletal machinery, the membrane system, and the cell wall. These compartments, often studied as independent units, show several molecular interactions and can influence the structure and organization of each other. The way the cell wall is constructed, the dynamics of the endomembrane system, and functions of the cytoskeleton suggest that these compartments are a molecular "continuum," which represents a link between the extracellular environment and the pollen tube cytoplasm. Several experimental approaches have been used to understand how these interactions may translate the pollen-pistil interactions into differential processes of pollen tube growth.
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Affiliation(s)
- Y Q Li
- Dipartimento Biologia Ambientale, Università di Siena, Italy
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16
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Miller DD, Scordilis SP, Hepler PK. Identification and localization of three classes of myosins in pollen tubes of Lilium longiflorum and Nicotiana alata. J Cell Sci 1995; 108 ( Pt 7):2549-63. [PMID: 7593296 DOI: 10.1242/jcs.108.7.2549] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The presence and localization of actin and myosin have been examined in pollen tubes of Lilium longiflorum and Nicotiana alata. Immunoblot analysis of pollen tube extracts with antibodies to actin, myosins IA and IB, myosin II, and myosin V reveals the presence of these contractile proteins. Immunofluorescence microscopy using various methods to preserve the pollen tubes; chemical fixation, rapid freeze fixation and freeze substitution (RF-FS) followed by rehydration or by embeddment in a methacrylate mixture, was performed to optimize preservation. Immunocytochemistry reaffirmed that actin is localized longitudinally in the active streaming lanes and near the cortical surface of the pollen tube. Myosin I was localized to the plasma membrane, larger organelles, the surface of the generative cell and the vegetative nucleus, whereas, myosin V was found in the vegetative cytoplasm in a punctate fashion representing smaller organelles. Myosin II subfragment 1 and light meromyosin were localized in a punctate fashion on the larger organelles throughout the vegetative cytoplasm. In addition, isolated generative cells and vegetative nuclei labeled only with the myosin I antibody. Competition studies indicated the specificity of the heterologous antibodies utilized in this study suggesting the presence of three classes of myosins in pollen. These results lead to the following hypothesis: Myosin I may move the generative cell and vegetative nucleus unidirectionally through the pollen tube to the tip, while myosin V moves the smaller organelles and myosins I and II move the larger organelles (bidirectionally) that are involved in growth.
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Affiliation(s)
- D D Miller
- Molecular and Cellular Biology Program, Morrill Science Center, University of Massachusetts, Amherst 01003, USA
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17
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Kinkema M, Wang H, Schiefelbein J. Molecular analysis of the myosin gene family in Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 1994; 26:1139-1153. [PMID: 7811972 DOI: 10.1007/bf00040695] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Myosin is believed to act as the molecular motor for many actin-based motility processes in eukaryotes. It is becoming apparent that a single species may possess multiple myosin isoforms, and at least seven distinct classes of myosin have been identified from studies of animals, fungi, and protozoans. The complexity of the myosin heavy-chain gene family in higher plants was investigated by isolating and characterizing myosin genomic and cDNA clones from Arabidopsis thaliana. Six myosin-like genes were identified from three polymerase chain reaction (PCR) products (PCR1, PCR11, PCR43) and three cDNA clones (ATM2, MYA2, MYA3). Sequence comparisons of the deduced head domains suggest that these myosins are members of two major classes. Analysis of the overall structure of the ATM2 and MYA2 myosins shows that they are similar to the previously-identified ATM1 and MYA1 myosins, respectively. The MYA3 appears to possess a novel tail domain, with five IQ repeats, a six-member imperfect repeat, and a segment of unique sequence. Northern blot analyses indicate that some of the Arabidopsis myosin genes are preferentially expressed in different plant organs. Combined with previous studies, these results show that the Arabidopsis genome contains at least eight myosin-like genes representing two distinct classes.
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Affiliation(s)
- M Kinkema
- Department of Biology, University of Michigan, Ann Arbor 48109
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18
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Pal M, Biswas S. A novel protein accumulated during maturation of the pods of the plant Impatiens balsamina. Mol Cell Biochem 1994; 130:111-20. [PMID: 8028590 DOI: 10.1007/bf01457392] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A high molecular weight protein has been isolated as a major polypeptide comprising 85% of the total extractable proteins in the fruit pericarp of the plant Impatiens balsamina. The protein has been purified to homogeneity following fractionation of the crude cell supernatant with ammonium sulphate, chromatography on Sepharose 4B and Sephacryl-S-300. This protein appeared to be a homo-tetramer consisting of subunits, Mr 75 K. Amino acid analysis showed the presence of more acidic amino acids, with an isoelectric point 5.8. The interaction of this protein with filamentous actin, both from rabbit muscle and Mung bean embryo was monitored by transmission electron microscopy, light scattering analysis, viscometry and sedimentation assay. This protein inhibited appreciably the polymerization of G-actin to F-actin.
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Affiliation(s)
- M Pal
- Department of Biochemistry, Bose Institute, Calcutta, India
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19
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Shimmen T, Yokota E. Physiological and Biochemical Aspects of Cytoplasmic Streaming. INTERNATIONAL REVIEW OF CYTOLOGY 1994. [DOI: 10.1016/s0074-7696(08)62097-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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20
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Regulation of Intracellular Movements in Plant Cells by Environmental Stimuli. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0074-7696(08)60429-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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21
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La Claire JW. Immunolocalization of myosin in intact and wounded cells of the green alga Ernodesmis verticillata (Kützing) Borgesen. PLANTA 1991; 184:209-217. [PMID: 24194072 DOI: 10.1007/bf00197949] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/29/1990] [Indexed: 06/02/2023]
Abstract
Myosin localization was examined in the coenocytic green alga E. verticillata using indirect immunofluorescence microscopy. A polyclonal antibody affinity-purified against the heavy chain of slime-mold myosin recognizes a 220000 to 230000 Mr protein that electrophoretically migrates slightly behind rabbit myosin. A second polypeptide of 85000 Mr is also consistently detected in immunoblots, indicating that two forms of myosin-like proteins may be present in these cells. In intact cells, myosin immunofluorescence is present on the chloroplast surfaces, in nuclei and in cytoplasmic strands between plastids. Myosin labeling also occurs in association with pyrenoids primarily in apical chloroplasts. During wound-induced cytoplasmic contractions, myosin is localized near the plasma membrane in longitudinal arrays superimposed over a reticulate pattern of fluorescence; both these patterns become apparent upon wounding. Double-label immunofluorescence of actin and myosin demonstrates that these arrays represent the longitudinal bundles of actin microfilaments and the actin-containing reticulum, the former being directly associated with contraction in these cells. These results indicate that both actin and myosin are associated with contractility in Ernodesmis, probably representing the apparatus and "molecular motor", respectively, which effect motility.
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Affiliation(s)
- J W La Claire
- Department of Botany, University of Texas, 78713, Austin, TX, USA
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22
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Meagher RB. Divergence and differential expression of actin gene families in higher plants. INTERNATIONAL REVIEW OF CYTOLOGY 1991; 125:139-63. [PMID: 2032783 DOI: 10.1016/s0074-7696(08)61218-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- R B Meagher
- Department of Genetics, University of Georgia, Athens 30602
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Villanueva MA, Ho SC, Wang JL. Isolation and characterization of one isoform of actin from cultured soybean cells. Arch Biochem Biophys 1990; 277:35-41. [PMID: 2306122 DOI: 10.1016/0003-9861(90)90546-b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cultured soybean cells (SB-1 cell line) were plasmolyzed and lyophilized. Extraction of the dried powder and fractionation yielded a polypeptide with the following key properties: (a) it has a molecular weight of approximately 45,000 and an isoelectric point of approximately 5.9; (b) it is immunologically cross-reactive with rabbit antibodies affinity purified against the Mr 45,000 polypeptide of calf thymus actin; (c) it is eluted from a DEAE-cellulose column at the same ionic strength as Acanthamoeba actin; (d) it yields peptide maps, after limited proteolysis with V8 protease, similar if not identical to those of rabbit muscle actin; and (e) it binds specifically to deoxyribonuclease I. These molecular and binding properties indicate that we have purified one isoform of actin from soybean cells.
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Affiliation(s)
- M A Villanueva
- Department of Biochemistry, Michigan State University, East Lansing 48824
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Cytoplasmic Streaming in Plant Cells. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/s0074-7696(08)60662-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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Tang XJ, Hepler PK, Scordilis SP. Immunochemical and immunocytochemical identification of a myosin heavy chain polypeptide in Nicotiana pollen tubes. J Cell Sci 1989; 92 ( Pt 4):569-74. [PMID: 2689460 DOI: 10.1242/jcs.92.4.569] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A myosin heavy chain polypeptide has been identified and localized in Nicotiana pollen tubes using monoclonal anti-myosin antibodies. The epitopes of these antibodies were found to reside on the myosin heavy chain head and rod portion and were, therefore, designated anti-S-1 (myosin S-1) and anti-LMM (light meromyosin). On Western blots of the total soluble pollen tube proteins, both anti-S-1 and anti-LMM label a polypeptide of approximately 175,000 Mr. Immunofluorescence microscopy shows that both antibodies yield numerous fluorescent spots throughout the whole length of the tube, often with an enrichment in the tube tip. These fluorescent spots are thought to represent vesicles and/or organelles in the pollen tubes. In addition to this common pattern, anti-S-1 stains both the generative cell and the vegetative nuclear envelope. The different staining patterns of the nucleus between anti-S-1 and anti-LMM may be caused by some organization and/or anchorage state of the myosin molecules on the nuclear surface that differs from those on the vesicles and/or organelles.
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Affiliation(s)
- X J Tang
- Department of Biochemistry, Beijing Agricultural University, China
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Vaughan MA, Vaughn KC. Effects of microfilament disrupters on microfilament distribution and morphology in maize root cells. HISTOCHEMISTRY 1987; 87:129-37. [PMID: 3623996 DOI: 10.1007/bf00533397] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Maize root tip cells were examined for the distribution of actin microfilaments in various cell types and to determine the effects of microfilament disrupters. Fluorescence microscopy on fixed, stabilized, squashed cells using the F-actin specific probe, rhodamine-labelled phalloidin, allowed for a three-dimensional visualization of actin microfilaments. Microfilaments were observed as long, meandering structures in root cap cells and meristematic cells, while those in immature vascular parenchyma were abundant in the thin band of cytoplasm and were long and less curved. By modifying standard electron microscopic fixation procedures, microfilaments in plant cells could be easily detected in all cell types. Treatment with cytochalasin B, cytochalasin D and lead acetate, compounds that interfere with microfilament related processes, re-organized the microfilaments into abnormal crossed and highly condensed masses. All the treatments affected not only the microfilaments but also the accumulation of secretory vesicles. The vivid demonstration of the effects of all of these microfilament disrupters on the number and size of Golgi vesicles indicates that these vesicles may depend on microfilaments for intracellular movement.
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28
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Côté GP, Albanesi JP, Ueno T, Hammer JA, Korn ED. Purification from Dictyostelium discoideum of a low-molecular-weight myosin that resembles myosin I from Acanthamoeba castellanii. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)89100-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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29
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Clayton L, Lloyd CW. Actin organization during the cell cycle in meristematic plant cells. Actin is present in the cytokinetic phragmoplast. Exp Cell Res 1985; 156:231-8. [PMID: 3965290 DOI: 10.1016/0014-4827(85)90277-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The distribution and organisation of F-actin during the cell cycle of meristematic root-tip cells of Allium was investigated using a rhodamine-labelled phalloidin to stain F-actin in isolated cell preparations. Such preparations could, in addition, be stained for tubulin by immunofluorescence, enabling a comparison between F-actin and microtubule distributions in the same cell. In interphase, an extensive array of actin-filament bundles was present in the cytoplasm of elongating cells, the bundles generally following the long axis of the cell and passing in close proximity to the nucleus. In contrast, the interphase microtubule array occupied the cortex of the cell and was oriented at right angles to the actin bundles. In smaller, isodiametric cells, microfilament arrays were present but less well developed. During cell division, phalloidin-specific staining was seen in the cytokinetic phragmoplast, and co-distributed with microtubules at all stages of cell plate formation; however, neither the pre-prophase band nor the mitotic spindle were stained with phalloidin. Co-distribution of F-actin and microtubules only occurs, therefore, at cytokinesis. The relationship between microfilaments and microtubules is discussed, together with the possible role of actin in the phragmoplast.
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Detmers PA, Carboni JM, Condeelis J. Localization of actin in Chlamydomonas using antiactin and NBD-phallacidin. CELL MOTILITY 1985; 5:415-30. [PMID: 2415259 DOI: 10.1002/cm.970050505] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have localized actin in gametes of Chlamydomonas reinhardi by two approaches: (1) indirect immunofluorescence with an affinity-purified antibody and (2) staining with NBD-phallacidin, a fluorescent reagent that binds only to F-actin [Barak et al, 1980, Proc Natl Acad Sci, 77:980-984]. Staining of either mating type "plus" (mt+) or "minus" (mt-) gametes with antiactin antibody resulted in similar fluorescent images: most of the actin was located peripherally along the lateral and posterior aspects of the cells. There was diffuse staining centrally, but the flagella did not stain. No brightly stained spot was observed near the mt+ mating structure, the site where the fertilization tubule elongates with concomitant polymerization of actin [Detmers et al, 1983, J Cell Biol, 97:522-532]. Gametes stained prior to mating with NBD-phallacidin showed no fluorescence above background, indicating that there were no concentrations of F-actin in these cells. This suggested that the cytoplasmic staining observed with antiactin represented primarily a nonfilamentous form of the protein. In mating gametes staining with NBD-phallacidin was detected only in the fertilization tubule, indicating that this was the only dense accumulation of filamentous actin within the cells. Mating gametes stained with antiactin antibody exhibited cytoplasmic fluorescence that was slightly more punctate than prior to mating, and the fertilization tubule was brightly stained. Our observations suggest that the site-specific polymerization of actin within the fertilization tubule occurs in the absence of a concentrated pool of actin subjacent to the mating structure.
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