1
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Yang L, Liu J, Wong CK, Lim BL. Movement of Lipid Droplets in the Arabidopsis Pollen Tube Is Dependent on the Actomyosin System. PLANTS (BASEL, SWITZERLAND) 2023; 12:2489. [PMID: 37447050 DOI: 10.3390/plants12132489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023]
Abstract
The growth of pollen tubes, which depends on actin filaments, is pivotal for plant reproduction. Pharmacological experiments showed that while oryzalin and brefeldin A treatments had no significant effect on the lipid droplets (LDs) trafficking, while 2,3-butanedione monoxime (BDM), latrunculin B, SMIFH2, and cytochalasin D treatments slowed down LDs trafficking, in such a manner that only residual wobbling was observed, suggesting that trafficking of LDs in pollen tube is related to F-actin. While the trafficking of LDs in the wild-type pollen tubes and in myo11-2, myo11b1-1, myo11c1-1, and myo11c2-1 single mutants and myo11a1-1/myo11a2-1 double mutant were normal, their trafficking slowed down in a myosin-XI double knockout (myo11c1-1/myo11c2-1) mutant. These observations suggest that Myo11C1 and Myo11C2 motors are involved in LDs movement in pollen tubes, and they share functional redundancy. Hence, LDs movement in Arabidopsis pollen tubes relies on the actomyosin system.
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Affiliation(s)
- Lang Yang
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Jinhong Liu
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ching-Kiu Wong
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Boon Leong Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
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2
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Ahmad HM, Alafari HA, Fiaz S, Alshaya DS, Toor S, Ijaz M, Rasool N, Attia KA, Zaynab M, Azmat S, Abushady AM, Chen Y. Genome-wide comparison and identification of myosin gene family in Arabidopsis thaliana and Helianthus annuus. Heliyon 2022; 8:e12070. [PMID: 36561675 PMCID: PMC9763749 DOI: 10.1016/j.heliyon.2022.e12070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/05/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022] Open
Abstract
Myosins are essential components of organelle trafficking in all the eukaryotic cells. Myosin driven movement plays a vital role in the development of pollen tubes, root hairs and root tips of flowering plants. The present research characterized the myosin genes in Arabidopsis thaliana and Helianthus annuus by using different computational tools. We discovered a total of 50 myosin genes and their splice variants in both pant species. Phylogenetic analysis indicated that myosin genes were divided into four subclasses. Chromosomal location revealed that myosin genes were located on all five chromosomes in A. thaliana, whereas they were present on nine chromosomes in H. annuus. Conserved motifs showed that conserved regions were closely similar within subgroups. Gene structure analysis showed that Atmyosin2.2 and Atmyosin2.3 had the highest number of introns/exons. Gene ontology analysis indicated that myosin genes were involved in vesicle transport along actin filament and cytoskeleton trafficking. Expression analysis showed that expression of myosin genes was higher during the flowering stage as compared to the seedling and budding stages. Tissue specific expression indicated that HanMYOSIN11.2, HanMYOSIN16.2 were highly expressed in stamen, whereas HanMYOSIN 2.2, HanMYOSIN 12.1 and HanMYOSIN 17.1 showed higher expression in nectary. This study enhance our understanding the function of myosins in plant development, and forms the basis for future research about the comparative genomics of plant myosin in other crop plants.
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Affiliation(s)
- Hafiz Muhammad Ahmad
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Pakistan,Corresponding author.
| | - Hayat Ali Alafari
- Deparment of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
| | - Sajid Fiaz
- Department of Plant Breeding and Genetics, University of Haripur, Haripur 22620, Pakistan,Corresponding author.
| | - Dalal S. Alshaya
- Deparment of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
| | - Sidra Toor
- Department of Life Sciences, University of Management and Technology, Lahore, Pakistan
| | - Munazza Ijaz
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Nouman Rasool
- Department of Plant Breeding and Genetics, University of Haripur, Haripur 22620, Pakistan
| | - Kotb A. Attia
- Center of Excellence in Biotechnology Research, King Saud University, P.O. Box 2455-11451, Riyadh 11451, Saudi Arabia,Department of Rice Biotechnology, RRTC, Institute of Field Crops, ARC, Sakha, 33177, Kafrelsheikh, Egypt
| | - Madiha Zaynab
- College of Life Science & Oceanography, Shenzhen University, China
| | - Saira Azmat
- Agriculture Extension and Adaptive Research, Agriculture Department, Government of Punjab, Pakistan
| | - Asmaa M. Abushady
- Biotechnology School, Nile University, 26th of July Corridor, Sheikh Zayed City, Giza, 12588, Egypt,Department of Genetics, Agriculture College, Ain Shams University, Cairo, Egypt
| | - Yinglong Chen
- School of Earth and Environment and UWA Institute of Agriculture, University of Western Australia, Australia
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3
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Stephan L, Jakoby M, Das A, Koebke E, Hülskamp M. Unravelling the molecular basis of the dominant negative effect of myosin XI tails on P-bodies. PLoS One 2021; 16:e0252327. [PMID: 34038472 PMCID: PMC8153422 DOI: 10.1371/journal.pone.0252327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 05/13/2021] [Indexed: 11/30/2022] Open
Abstract
The directional movement and positioning of organelles and macromolecules is essential for regulating and maintaining cellular functions in eukaryotic cells. In plants, these processes are actin-based and driven by class XI myosins, which transport various cargos in a directed manner. As the analysis of myosin function is challenging due to high levels of redundancy, dominant negative acting truncated myosins have frequently been used to study intracellular transport processes. A comparison of the dominant negative effect of the coiled-coil domains and the GTD domains revealed a much stronger inhibition of P-body movement by the GTD domains. In addition, we show that the GTD domain does not inhibit P-body movement when driven by a hybrid myosin in which the GTD domain was replaced by DCP2. These data suggest that the dominant negative effect of myosin tails involves a competition of the GTD domains for cargo binding sites.
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Affiliation(s)
- Lisa Stephan
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Marc Jakoby
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Arijit Das
- Faculty of Medicine, Institute of Medical Statistics and Computational Biology & Institute for Diagnostic and Interventional Radiology, University Hospital Cologne, Cologne, Germany
| | - Eva Koebke
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Martin Hülskamp
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
- * E-mail:
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4
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Duan Z, Tanaka M, Kanazawa T, Haraguchi T, Takyu A, Era A, Ueda T, Ito K, Tominaga M. Characterization of ancestral myosin XI from Marchantia polymorpha by heterologous expression in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:460-473. [PMID: 32717107 PMCID: PMC7689712 DOI: 10.1111/tpj.14937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/16/2020] [Indexed: 05/30/2023]
Abstract
Previous studies have revealed duplications and diversification of myosin XI genes between angiosperms and bryophytes; however, the functional differentiation and conservation of myosin XI between them remain unclear. Here, we identified a single myosin XI gene from the liverwort Marchantia polymorpha (Mp). The molecular properties of Mp myosin XI are similar to those of Arabidopsis myosin XIs responsible for cytoplasmic streaming, suggesting that the motor function of myosin XI is able to generate cytoplasmic streaming. In cultured Arabidopsis cells, transiently expressed green fluorescent protein (GFP)-fused Mp myosin XI was observed as some intracellular structures moving along the F-actin. These intracellular structures were co-localized with motile endoplasmic reticulum (ER) strands, suggesting that Mp myosin XI binds to the ER and generates intracellular transport in Arabidopsis cells. The tail domain of Mp myosin XI was co-localized with that of Arabidopsis myosin XI-2 and XI-K, suggesting that all these myosin XIs bind to common cargoes. Furthermore, expression of GFP-fused Mp myosin XI rescued the defects of growth, cytoplasmic streaming and actin organization in Arabidopsis multiple myosin XI knockout mutants. The heterologous expression experiments demonstrated the cellular and physiological competence of Mp myosin XI in Arabidopsis. However, the average velocity of organelle transport in Marchantia rhizoids was 0.04 ± 0.01 μm s-1 , which is approximately one-hundredth of that in Arabidopsis cells. Taken together, our results suggest that the molecular properties of myosin XI are conserved, but myosin XI-driven intracellular transport in vivo would be differentiated from bryophytes to angiosperms.
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Affiliation(s)
- Zhongrui Duan
- Faculty of Education and Integrated Arts and SciencesWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
| | - Misato Tanaka
- Graduate School of Science and EngineeringWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
| | - Takehiko Kanazawa
- Division of Cellular DynamicsNational Institute for Basic BiologyNishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
- Department of Basic BiologySOKENDAINishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
| | - Takeshi Haraguchi
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Akiko Takyu
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Atsuko Era
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuTokyo113‐0033Japan
| | - Takashi Ueda
- Division of Cellular DynamicsNational Institute for Basic BiologyNishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
- Department of Basic BiologySOKENDAINishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
| | - Kohji Ito
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and SciencesWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
- Graduate School of Science and EngineeringWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
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Genome-Wide Identification and Comparative Analysis of Myosin Gene Family in Four Major Cotton Species. Genes (Basel) 2020; 11:genes11070731. [PMID: 32630134 PMCID: PMC7397272 DOI: 10.3390/genes11070731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 11/16/2022] Open
Abstract
Myosin protein as a molecular motor, binding with Actin, plays a significant role in various physiological activities such as cell division, movement, migration, and morphology; however, there are only a few studies on plant Myosin gene family, particularly in cotton. A total of 114 Myosin genes were found in Gossypium hirsutum, Gossypium barbadense, Gossypium raimondii, and Gossypium arboreum. All Myosins could be grouped into six groups, and for each group of these genes, similar gene structures are found. Study of evolution suggested that the whole genome duplications event occurring about 13-20 MYA (millions of years ago) is the key explanation for Myosins expanse in cotton. Cis-element and qPCR analysis revealed that plant hormones such as abscisic acid, methyl jasmonate, and salicylic acid can control the expression of Myosins. This research provides useful information on the function of Myosin genes in regulating plant growth, production, and fiber elongation for further studies.
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Plant Lipid Bodies Traffic on Actin to Plasmodesmata Motorized by Myosin XIs. Int J Mol Sci 2020; 21:ijms21041422. [PMID: 32093159 PMCID: PMC7073070 DOI: 10.3390/ijms21041422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
Late 19th-century cytologists observed tiny oil drops in shoot parenchyma and seeds, but it was discovered only in 1972 that they were bound by a half unit-membrane. Later, it was found that lipid bodies (LBs) arise from the endoplasmic reticulum. Seeds are known to be packed with static LBs, coated with the LB-specific protein OLEOSIN. As shown here, apices of Populustremula x P. tremuloides also express OLEOSIN genes and produce potentially mobile LBs. In developing buds, PtOLEOSIN (PtOLE) genes were upregulated, especially PtOLE6, concomitant with LB accumulation. To investigate LB mobility and destinations, we transformed Arabidopsis with PtOLE6-eGFP. We found that PtOLE6-eGFP fusion protein co-localized with Nile Red-stained LBs in all cell types. Moreover, PtOLE6-eGFP-tagged LBs targeted plasmodesmata, identified by the callose marker aniline blue. Pharmacological experiments with brefeldin, cytochalasin D, and oryzalin showed that LB-trafficking requires F-actin, implying involvement of myosin motors. In a triple myosin-XI knockout (xi-k/1/2), transformed with PtOLE6-eGFP, trafficking of PtOLE6-eGFP-tagged LBs was severely impaired, confirming that they move on F-actin, motorized by myosin XIs. The data reveal that LBs and OLEOSINs both function in proliferating apices and buds, and that directional trafficking of LBs to plasmodesmata requires the actomyosin system.
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7
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Osterrieder A, Sparkes IA, Botchway SW, Ward A, Ketelaar T, de Ruijter N, Hawes C. Stacks off tracks: a role for the golgin AtCASP in plant endoplasmic reticulum-Golgi apparatus tethering. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3339-3350. [PMID: 28605454 PMCID: PMC5853478 DOI: 10.1093/jxb/erx167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/25/2017] [Indexed: 05/18/2023]
Abstract
The plant Golgi apparatus modifies and sorts incoming proteins from the endoplasmic reticulum (ER) and synthesizes cell wall matrix material. Plant cells possess numerous motile Golgi bodies, which are connected to the ER by yet to be identified tethering factors. Previous studies indicated a role for cis-Golgi plant golgins, which are long coiled-coil domain proteins anchored to Golgi membranes, in Golgi biogenesis. Here we show a tethering role for the golgin AtCASP at the ER-Golgi interface. Using live-cell imaging, Golgi body dynamics were compared in Arabidopsis thaliana leaf epidermal cells expressing fluorescently tagged AtCASP, a truncated AtCASP-ΔCC lacking the coiled-coil domains, and the Golgi marker STtmd. Golgi body speed and displacement were significantly reduced in AtCASP-ΔCC lines. Using a dual-colour optical trapping system and a TIRF-tweezer system, individual Golgi bodies were captured in planta. Golgi bodies in AtCASP-ΔCC lines were easier to trap and the ER-Golgi connection was more easily disrupted. Occasionally, the ER tubule followed a trapped Golgi body with a gap, indicating the presence of other tethering factors. Our work confirms that the intimate ER-Golgi association can be disrupted or weakened by expression of truncated AtCASP-ΔCC and suggests that this connection is most likely maintained by a golgin-mediated tethering complex.
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Affiliation(s)
- Anne Osterrieder
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, UK
| | - Imogen A Sparkes
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, UK
| | - Stan W Botchway
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, UK
| | - Andy Ward
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, UK
| | - Tijs Ketelaar
- Laboratory of Cell Biology, Wageningen University, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Norbert de Ruijter
- Laboratory of Cell Biology, Wageningen University, Droevendaalsesteeg, Wageningen, The Netherlands
| | - Chris Hawes
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, UK
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8
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Luo Y, Scholl S, Doering A, Zhang Y, Irani NG, Rubbo SD, Neumetzler L, Krishnamoorthy P, Van Houtte I, Mylle E, Bischoff V, Vernhettes S, Winne J, Friml J, Stierhof YD, Schumacher K, Persson S, Russinova E. V-ATPase activity in the TGN/EE is required for exocytosis and recycling in Arabidopsis. NATURE PLANTS 2015; 1:15094. [PMID: 27250258 PMCID: PMC4905525 DOI: 10.1038/nplants.2015.94] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 06/03/2015] [Indexed: 05/18/2023]
Abstract
In plants, vacuolar H(+)-ATPase (V-ATPase) activity acidifies both the trans-Golgi network/early endosome (TGN/EE) and the vacuole. This dual V-ATPase function has impeded our understanding of how the pH homeostasis within the plant TGN/EE controls exo- and endocytosis. Here, we show that the weak V-ATPase mutant deetiolated3 (det3) displayed a pH increase in the TGN/EE, but not in the vacuole, strongly impairing secretion and recycling of the brassinosteroid receptor and the cellulose synthase complexes to the plasma membrane, in contrast to mutants lacking tonoplast-localized V-ATPase activity only. The brassinosteroid insensitivity and the cellulose deficiency defects in det3 were tightly correlated with reduced Golgi and TGN/EE motility. Thus, our results provide strong evidence that acidification of the TGN/EE, but not of the vacuole, is indispensable for functional secretion and recycling in plants.
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Affiliation(s)
- Yu Luo
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Stefan Scholl
- Developmental Biology of Plants, Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Anett Doering
- Max-Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Yi Zhang
- Max-Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Niloufer G. Irani
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Simone Di Rubbo
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Lutz Neumetzler
- Max-Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany
| | | | - Isabelle Van Houtte
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Evelien Mylle
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
| | - Volker Bischoff
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, 78000 Versailles, France
- AgroParisTech,Institut Jean-Pierre Bourgin, 78000 Versailles, France
| | - Samantha Vernhettes
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, 78000 Versailles, France
- AgroParisTech,Institut Jean-Pierre Bourgin, 78000 Versailles, France
| | - Johan Winne
- Department of Organic Chemistry, Polymer Chemistry Research Group and Laboratory for Organic Synthesis, Ghent University, 9000 Gent, Belgium
| | - Jiří Friml
- Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria
| | - York-Dieter Stierhof
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Karin Schumacher
- Developmental Biology of Plants, Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
- , , and
| | - Staffan Persson
- Max-Planck Institute for Molecular Plant Physiology, 14476 Potsdam, Germany
- Australian Research Council, Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia
- , , and
| | - Eugenia Russinova
- Department of Plant Systems Biology, VIB, 9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- , , and
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Okamoto K, Ueda H, Shimada T, Tamura K, Kato T, Tasaka M, Morita MT, Hara-Nishimura I. Regulation of organ straightening and plant posture by an actin-myosin XI cytoskeleton. NATURE PLANTS 2015; 1:15031. [PMID: 27247032 DOI: 10.1038/nplants.2015.31] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/17/2015] [Indexed: 05/08/2023]
Abstract
Plants are able to bend nearly every organ in response to environmental stimuli such as gravity and light(1,2). After this first phase, the responses to stimuli are restrained by an independent mechanism, or even reversed, so that the organ will stop bending and attain its desired posture. This phenomenon of organ straightening has been called autotropism(3) and autostraightening(4) and modelled as proprioception(5). However, the machinery that drives organ straightening and where it occurs are mostly unknown. Here, we show that the straightening of inflorescence stems is regulated by an actin-myosin XI cytoskeleton in specialized immature fibre cells that are parallel to the stem and encircle it in a thin band. Arabidopsis mutants defective in myosin XI (specifically XIf and XIk) or ACTIN8 exhibit hyperbending of stems in response to gravity, an effect independent of the physical properties of the shoots. The actin-myosin XI cytoskeleton enables organs to attain their new position more rapidly than would an oscillating series of diminishing overshoots in environmental stimuli. We propose that the long actin filaments in elongating fibre cells act as a bending tensile sensor to perceive the organ's posture and trigger the straightening system.
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Affiliation(s)
- Keishi Okamoto
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Haruko Ueda
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Tomoo Shimada
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kentaro Tamura
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Takehide Kato
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Masao Tasaka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Miyo Terao Morita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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10
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Oda Y, Iida Y, Nagashima Y, Sugiyama Y, Fukuda H. Novel coiled-coil proteins regulate exocyst association with cortical microtubules in xylem cells via the conserved oligomeric golgi-complex 2 protein. PLANT & CELL PHYSIOLOGY 2015; 56:277-86. [PMID: 25541219 DOI: 10.1093/pcp/pcu197] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Xylem vessel cells develop secondary cell walls in distinct patterns. Cortical microtubules are rearranged into distinct patterns and regulate secondary cell wall deposition; however, it is unclear how exocytotic membrane trafficking is linked to cortical microtubules. Here, we show that the novel coiled-coil proteins vesicle tethering 1 (VETH1) and VETH2 recruit EXO70A1, an exocyst subunit essential for correct patterning of secondary cell wall deposition, to cortical microtubules via the conserved oligomeric Golgi complex (COG) 2 protein. VETH1 and VETH2 encode an uncharacterized domain of an unknown function designated DUF869, and were preferentially up-regulated in xylem cells. VETH1-green fluorescent protein (GFP) and VETH2-GFP co-localized at novel vesicle-like small compartments, which exhibited microtubule plus-end-directed and end-tracking dynamics. VETH1 and VETH2 interacted with COG2, and this interaction promoted the association between cortical microtubules and EXO70A1 These results suggest that the VETH-COG2 complex ensures the correct secondary cell wall deposition pattern by recruiting exocyst components to cortical microtubules.
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Affiliation(s)
- Yoshihisa Oda
- Center for Frontier Research, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540 Japan Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka, 411 8540 Japan Precursory Research for Embryonic Science and Technology Project, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 Japan
| | - Yuki Iida
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Yoshinobu Nagashima
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Yuki Sugiyama
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Hiroo Fukuda
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
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11
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Hawes C, Kiviniemi P, Kriechbaumer V. The endoplasmic reticulum: a dynamic and well-connected organelle. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:50-62. [PMID: 25319240 DOI: 10.1111/jipb.12297] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/09/2014] [Indexed: 06/04/2023]
Abstract
The endoplasmic reticulum forms the first compartment in a series of organelles which comprise the secretory pathway. It takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.
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Affiliation(s)
- Chris Hawes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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Baker A, Paudyal R. The life of the peroxisome: from birth to death. CURRENT OPINION IN PLANT BIOLOGY 2014; 22:39-47. [PMID: 25261594 DOI: 10.1016/j.pbi.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/24/2014] [Accepted: 09/05/2014] [Indexed: 06/03/2023]
Abstract
Peroxisomes are dynamic and metabolically plastic organelles. Their multiplicity of functions impacts on many aspects of plant development and survival. New functions for plant peroxisomes such as in the synthesis of biotin, ubiquinone and phylloquinone are being uncovered and their role in generating reactive oxygen species (ROS) and reactive nitrogen species (RNS) as signalling hubs in defence and development is becoming appreciated. Understanding of the biogenesis of peroxisomes, mechanisms of import and turnover of their protein complement, and the wholesale destruction of the organelle by specific autophagic processes is giving new insight into the ways that plants can adjust peroxisome function in response to changing needs.
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Affiliation(s)
- Alison Baker
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - Rupesh Paudyal
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, UK
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13
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Higa T, Suetsugu N, Wada M. Plant nuclear photorelocation movement. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2873-2881. [PMID: 24336444 DOI: 10.1093/jxb/ert414] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Organelle movement and positioning are essential for proper cellular function. A nucleus moves dynamically during cell division and differentiation and in response to environmental changes in animal, fungal, and plant cells. Nuclear movement is well-studied and the mechanisms have been mostly elucidated in animal and fungal cells, but not in plant cells. In prothallial cells of the fern Adiantum capillus-veneris and leaf cells of the flowering plant Arabidopsis thaliana, light induces nuclear movement and nuclei change their position according to wavelength, intensity, and direction of light. This nuclear photorelocation movement shows some common features with the photorelocation movement of chloroplasts, which is one of the best-characterized plant organelle movements. This review summarizes nuclear movement and positioning in plant cells, especially plant-specific nuclear photorelocation movement and discusses the relationship between nuclear photorelocation movement and chloroplast photorelocation movement.
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Affiliation(s)
- Takeshi Higa
- Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Noriyuki Suetsugu
- Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Masamitsu Wada
- Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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14
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Steffens A, Jaegle B, Tresch A, Hülskamp M, Jakoby M. Processing-body movement in Arabidopsis depends on an interaction between myosins and DECAPPING PROTEIN1. PLANT PHYSIOLOGY 2014; 164:1879-92. [PMID: 24525673 PMCID: PMC3982750 DOI: 10.1104/pp.113.233031] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 02/12/2014] [Indexed: 05/18/2023]
Abstract
Processing (P)-bodies are cytoplasmic RNA protein aggregates responsible for the storage, degradation, and quality control of translationally repressed messenger RNAs in eukaryotic cells. In mammals, P-body-related RNA and protein exchanges are actomyosin dependent, whereas P-body movement requires intact microtubules. In contrast, in plants, P-body motility is actin based. In this study, we show the direct interaction of the P-body core component DECAPPING PROTEIN1 (DCP1) with the tails of different unconventional myosins in Arabidopsis (Arabidopsis thaliana). By performing coexpression studies with AtDCP1, dominant-negative myosin fragments, as well as functional full-length myosin XI-K, the association of P-bodies and myosins was analyzed in detail. Finally, the combination of mutant analyses and characterization of P-body movement patterns showed that myosin XI-K is essential for fast and directed P-body transport. Together, our data indicate that P-body movement in plants is governed by myosin XI members through direct binding to AtDCP1 rather than through an adapter protein, as known for membrane-coated organelles. Interspecies and intraspecies interaction approaches with mammalian and yeast protein homologs suggest that this mechanism is evolutionarily conserved among eukaryotes.
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15
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Lv DW, Ge P, Zhang M, Cheng ZW, Li XH, Yan YM. Integrative network analysis of the signaling cascades in seedling leaves of bread wheat by large-scale phosphoproteomic profiling. J Proteome Res 2014; 13:2381-95. [PMID: 24679076 DOI: 10.1021/pr401184v] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Here, we conducted the first large-scale leaf phosphoproteome analysis of two bread wheat cultivars by liquid chromatography-tandem mass spectrometry. Altogether, 1802 unambiguous phosphorylation sites representing 1175 phosphoproteins implicated in various molecular functions and cellular processes were identified by gene ontology enrichment analysis. Among the 1175 phosphoproteins, 141 contained 3-10 phosphorylation sites. The phosphorylation sites were located more frequently in the N- and C-terminal regions than in internal regions, and ∼70% were located outside the conserved regions. Conservation analysis showed that 90.5% of the phosphoproteins had phosphorylated orthologs in other plant species. Eighteen significantly enriched phosphorylation motifs, of which six were new wheat phosphorylation motifs, were identified. In particular, 52 phosphorylated transcription factors (TFs), 85 protein kinases (PKs), and 16 protein phosphatases (PPs) were classified and analyzed in depth. All the Tyr phosphorylation sites were in PKs such as mitogen-activated PKs (MAPKs) and SHAGGY-like kinases. A complicated cross-talk phosphorylation regulatory network based on PKs such as Snf1-related kinases (SnRKs), calcium-dependent PKs (CDPKs), and glycogen synthase kinase 3 (GSK3) and PPs including PP2C, PP2A, and BRI1 suppressor 1 (BSU1)-like protein (BSL) was constructed and was found to be potentially involved in rapid leaf growth. Our results provide a series of phosphoproteins and phosphorylation sites in addition to a potential network of phosphorylation signaling cascades in wheat seedling leaves.
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Affiliation(s)
- Dong-Wen Lv
- College of Life Science, Capital Normal University , 100048 Beijing, China
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16
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Park E, Nebenführ A. Myosin XIK of Arabidopsis thaliana accumulates at the root hair tip and is required for fast root hair growth. PLoS One 2013; 8:e76745. [PMID: 24116145 PMCID: PMC3792037 DOI: 10.1371/journal.pone.0076745] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 08/28/2013] [Indexed: 11/19/2022] Open
Abstract
Myosin motor proteins are thought to carry out important functions in the establishment and maintenance of cell polarity by moving cellular components such as organelles, vesicles, or protein complexes along the actin cytoskeleton. In Arabidopsis thaliana, disruption of the myosin XIK gene leads to reduced elongation of the highly polar root hairs, suggesting that the encoded motor protein is involved in this cell growth. Detailed live-cell observations in this study revealed that xik root hairs elongated more slowly and stopped growth sooner than those in wild type. Overall cellular organization including the actin cytoskeleton appeared normal, but actin filament dynamics were reduced in the mutant. Accumulation of RabA4b-containing vesicles, on the other hand, was not significantly different from wild type. A functional YFP-XIK fusion protein that could complement the mutant phenotype accumulated at the tip of growing root hairs in an actin-dependent manner. The distribution of YFP-XIK at the tip, however, did not match that of the ER or several tip-enriched markers including CFP-RabA4b. We conclude that the myosin XIK is required for normal actin dynamics and plays a role in the subapical region of growing root hairs to facilitate optimal growth.
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Affiliation(s)
- Eunsook Park
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
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17
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Affiliation(s)
- M Amanda Hartman
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
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18
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Furt F, Liu YC, Bibeau JP, Tüzel E, Vidali L. Apical myosin XI anticipates F-actin during polarized growth of Physcomitrella patens cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:417-428. [PMID: 23020796 DOI: 10.1111/tpj.12039] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/07/2012] [Accepted: 09/27/2012] [Indexed: 05/28/2023]
Abstract
Tip growth is essential for land colonization by bryophytes, plant sexual reproduction and water and nutrient uptake. Because this specialized form of polarized cell growth requires both a dynamic actin cytoskeleton and active secretion, it has been proposed that the F-actin-associated motor myosin XI is essential for this process. Nevertheless, a spatial and temporal relationship between myosin XI and F-actin during tip growth is not known in any plant cell. Here, we use the highly polarized cells of the moss Physcomitrella patens to show that myosin XI and F-actin localize, in vivo, at the same apical domain and that both signals fluctuate. Surprisingly, phase analysis shows that increase in myosin XI anticipates that of F-actin; in contrast, myosin XI levels at the tip fluctuate in identical phase with a vesicle marker. Pharmacological analysis using a low concentration of the actin polymerization inhibitor latrunculin B showed that the F-actin at the tip can be significantly diminished while myosin XI remains elevated in this region, suggesting that a mechanism exists to cluster myosin XI-associated structures at the cell's apex. In addition, this approach uncovered a mechanism for actin polymerization-dependent motility in the moss cytoplasm, where myosin XI-associated structures seem to anticipate and organize the actin polymerization machinery. From our results, we inferred a model where the interaction between myosin XI-associated vesicular structures and F-actin polymerization-driven motility function at the cell's apex to maintain polarized cell growth. We hypothesize this is a general mechanism for the participation of myosin XI and F-actin in tip growing cells.
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Affiliation(s)
- Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
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19
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Sparkes I, Brandizzi F. Fluorescent protein-based technologies: shedding new light on the plant endomembrane system. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:96-107. [PMID: 22449045 DOI: 10.1111/j.1365-313x.2011.04884.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Without doubt, GFP and spectral derivatives have revolutionized the way biologists approach their journey toward the discovery of how plant cells function. It is fascinating that in its early days GFP was used merely for localization studies, but as time progressed researchers successfully explored new avenues to push the power of GFP technology to reach new and exciting research frontiers. This has had a profound impact on the way we can now study complex and dynamic systems such as plant endomembranes. Here we briefly describe some of the approaches where GFP has revolutionized in vivo studies of protein distribution and dynamics and focus on two emerging approaches for the application of GFP technology in plant endomembranes, namely optical tweezers and forward genetics approaches, which are based either on the light or on genetic manipulation of secretory organelles to gain insights on the factors that control their activities and integrity.
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Affiliation(s)
- Imogen Sparkes
- Biosciences,College of Life and Environmental Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter, UK
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20
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Sparkes I. Recent advances in understanding plant myosin function: life in the fast lane. MOLECULAR PLANT 2011; 4:805-812. [PMID: 21772028 DOI: 10.1093/mp/ssr063] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Plant myosins are required for organelle movement, and a role in actin organization has recently come to light. Myosin mutants display several gross morphological phenotypes, the most severe being dwarfism and reduced fecundity, and there is a correlation between reduced organelle movement and morphological defects. This review aims to discuss recent findings in plants relating to the role of myosins in actin dynamics, development, and organelle movement, more specifically the endoplasmic reticulum (ER). One overarching theme is that there still appear to be more questions than answers relating to plant myosin function and regulation.
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Affiliation(s)
- Imogen Sparkes
- School of Life Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK.
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21
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Hartman MA, Finan D, Sivaramakrishnan S, Spudich JA. Principles of unconventional myosin function and targeting. Annu Rev Cell Dev Biol 2011; 27:133-55. [PMID: 21639800 DOI: 10.1146/annurev-cellbio-100809-151502] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Unconventional myosins are a superfamily of actin-based motors implicated in diverse cellular processes. In recent years, much progress has been made in describing their biophysical properties, and headway has been made into analyzing their cellular functions. Here, we focus on the principles that guide in vivo motor function and targeting to specific cellular locations. Rather than describe each motor comprehensively, we outline the major themes that emerge from research across the superfamily and use specific examples to illustrate each. In presenting the data in this format, we seek to identify open questions in each field as well as to point out commonalities between them. To advance our understanding of myosins' roles in vivo, clearly we must identify their cellular cargoes and the protein complexes that regulate motor attachment to fully appreciate their functions on the cellular and developmental levels.
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Affiliation(s)
- M Amanda Hartman
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
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22
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Peremyslov VV, Mockler TC, Filichkin SA, Fox SE, Jaiswal P, Makarova KS, Koonin EV, Dolja VV. Expression, splicing, and evolution of the myosin gene family in plants. PLANT PHYSIOLOGY 2011; 155:1191-204. [PMID: 21233331 PMCID: PMC3046578 DOI: 10.1104/pp.110.170720] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Plants possess two myosin classes, VIII and XI. The myosins XI are implicated in organelle transport, filamentous actin organization, and cell and plant growth. Due to the large size of myosin gene families, knowledge of these molecular motors remains patchy. Using deep transcriptome sequencing and bioinformatics, we systematically investigated myosin genes in two model plants, Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon). We improved myosin gene models and found that myosin genes undergo alternative splicing. We experimentally validated the gene models for Arabidopsis myosin XI-K, which plays the principal role in cell interior dynamics, as well as for its Brachypodium ortholog. We showed that the Arabidopsis gene dubbed HDK (for headless derivative of myosin XI-K), which emerged through a partial duplication of the XI-K gene, is developmentally regulated. A gene with similar architecture was also found in Brachypodium. Our analyses revealed two predominant patterns of myosin gene expression, namely pollen/stamen-specific and ubiquitous expression throughout the plant. We also found that several myosins XI can be rhythmically expressed. Phylogenetic reconstructions indicate that the last common ancestor of the angiosperms possessed two myosins VIII and five myosins XI, many of which underwent additional lineage-specific duplications.
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Tilsner J, Amari K, Torrance L. Plasmodesmata viewed as specialised membrane adhesion sites. PROTOPLASMA 2011; 248:39-60. [PMID: 20938697 DOI: 10.1007/s00709-010-0217-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 09/27/2010] [Indexed: 05/20/2023]
Abstract
A significant amount of work has been expended to identify the elusive components of plasmodesmata (PD) to help understand their structure, as well as how proteins are targeted to them. This review focuses on the role that lipid membranes may play in defining PD both structurally and as subcellular targeting addresses. Parallels are drawn to findings in other areas of research which focus on the lateral segregation of membrane domains and the generation of three-dimensional organellar shapes from flat lipid bilayers. We conclude that consideration of the protein-lipid interactions in cell biological studies of PD components and PD-targeted proteins may yield new insights into some of the many open questions regarding these unique structures.
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Affiliation(s)
- Jens Tilsner
- Institute of Molecular Plant Sciences, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JH, UK.
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24
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Suetsugu N, Dolja VV, Wada M. Why have chloroplasts developed a unique motility system? PLANT SIGNALING & BEHAVIOR 2010; 5:1190-6. [PMID: 20855973 PMCID: PMC3115347 DOI: 10.4161/psb.5.10.12802] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 06/22/2010] [Indexed: 05/17/2023]
Abstract
Organelle movement in plants is dependent on actin filaments with most of the organelles being transported along the actin cables by class XI myosins. Although chloroplast movement is also actin filament-dependent, a potential role of myosin motors in this process is poorly understood. Interestingly, chloroplasts can move in any direction, and change the direction within short time periods, suggesting that chloroplasts use the newly formed actin filaments rather than preexisting actin cables. Furthermore, the data on myosin gene knockouts and knockdowns in Arabidopsis and tobacco do not support myosins' XI role in chloroplast movement. Our recent studies revealed that chloroplast movement and positioning are mediated by the short actin filaments localized at chloroplast periphery (cp-actin filaments) rather than cytoplasmic actin cables. The accumulation of cp-actin filaments depends on kinesin-like proteins, KAC1 and KAC2, as well as on a chloroplast outer membrane protein CHUP1. We propose that plants evolved a myosin XI-independent mechanism of the actin-based chloroplast movement that is distinct from the mechanism used by other organelles.
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Affiliation(s)
- Noriyuki Suetsugu
- Department of Biology; Faculty of Sciences; Kyushu University; Fukuoka, Japan
| | - Valerian V Dolja
- Department of Botany and Plant Pathology; Center for Genome Research and Biocomputing; Oregon State University; Corvallis, OR USA
| | - Masamitsu Wada
- Department of Biology; Faculty of Sciences; Kyushu University; Fukuoka, Japan
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Abstract
Plant peroxisomes are extremely dynamic, moving and undergoing changes of shape in response to metabolic and environmental signals. Matrix proteins are imported via one of two import pathways, depending on the targeting signal within the protein. Each pathway has a specific receptor but utilizes common membrane-bound translocation machinery. Current models invoke receptor recycling, which may involve cycles of ubiquitination. Some components of the import machinery may also play a role in proteolytic turnover of matrix proteins, prompting parallels with the endoplasmic-reticulum-associated degradation pathway. Peroxisome membrane proteins, some of which are imported post-translationally, others of which may traffic to peroxisomes via the endoplasmic reticulum, use distinct proteinaceous machinery. The isolation of mutants defective in peroxisome biogenesis has served to emphasize the important role of peroxisomes at all stages of the plant life cycle.
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26
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Organelle biogenesis and positioning in plants. Biochem Soc Trans 2010; 38:729-32. [PMID: 20491657 DOI: 10.1042/bst0380729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The biogenesis and positioning of organelles involves complex interacting processes and precise control. Progress in our understanding is being made rapidly as advances in analysing the nuclear and organellar genome and proteome combine with developments in live-cell microscopy and manipulation at the subcellular level. This paper introduces the collected papers resulting from Organelle Biogenesis and Positioning in Plants, the 2009 Biochemical Society Annual Symposium. Including papers on the nuclear envelope and all major organelles, it considers current knowledge and progress towards unifying themes that will elucidate the mechanisms by which cells generate the correct complement of organelles and adapt and change it in response to environmental and developmental signals.
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