1
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Tang HB, Wang J, Wang L, Shang GD, Xu ZG, Mai YX, Liu YT, Zhang TQ, Wang JW. Anisotropic cell growth at the leaf base promotes age-related changes in leaf shape in Arabidopsis thaliana. THE PLANT CELL 2023; 35:1386-1407. [PMID: 36748203 PMCID: PMC10118278 DOI: 10.1093/plcell/koad031] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 05/17/2023]
Abstract
Plants undergo extended morphogenesis. The shoot apical meristem (SAM) allows for reiterative development and the formation of new structures throughout the life of the plant. Intriguingly, the SAM produces morphologically different leaves in an age-dependent manner, a phenomenon known as heteroblasty. In Arabidopsis thaliana, the SAM produces small orbicular leaves in the juvenile phase, but gives rise to large elliptical leaves in the adult phase. Previous studies have established that a developmental decline of microRNA156 (miR156) is necessary and sufficient to trigger this leaf shape switch, although the underlying mechanism is poorly understood. Here we show that the gradual increase in miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE transcription factors with age promotes cell growth anisotropy in the abaxial epidermis at the base of the leaf blade, evident by the formation of elongated giant cells. Time-lapse imaging and developmental genetics further revealed that the establishment of adult leaf shape is tightly associated with the longitudinal cell expansion of giant cells, accompanied by a prolonged cell proliferation phase in their vicinity. Our results thus provide a plausible cellular mechanism for heteroblasty in Arabidopsis, and contribute to our understanding of anisotropic growth in plants.
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Affiliation(s)
- Hong-Bo Tang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
- University of Chinese Academy of Sciences (UCAS), Shanghai 200032, China
| | - Juan Wang
- School of Statistics and Mathematics, Inner Mongolia University of Finance and Economics, Huhehaote 010070, China
| | - Long Wang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
| | - Guan-Dong Shang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
- University of Chinese Academy of Sciences (UCAS), Shanghai 200032, China
| | - Zhou-Geng Xu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
- University of Chinese Academy of Sciences (UCAS), Shanghai 200032, China
| | - Yan-Xia Mai
- Core Facility Center of CEMPS, Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
| | - Ye-Tong Liu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
- Shanghai Normal University, College of Life and Environmental Sciences, Shanghai 200234, China
| | - Tian-Qi Zhang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
| | - Jia-Wei Wang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Shanghai 200032, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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2
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Macke AC, Kelly MS, Varikoti RA, Mullen S, Groves D, Forbes C, Dima RI. Microtubule Severing Enzymes Oligomerization and Allostery: A Tale of Two Domains. J Phys Chem B 2022; 126:10569-10586. [PMID: 36475672 DOI: 10.1021/acs.jpcb.2c05288] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Severing proteins are nanomachines from the AAA+ (ATPases associated with various cellular activities) superfamily whose function is to remodel the largest cellular filaments, microtubules. The standard AAA+ machines adopt hexameric ring structures for functional reasons, while being primarily monomeric in the absence of the nucleotide. Both major severing proteins, katanin and spastin, are believed to follow this trend. However, studies proposed that they populate lower-order oligomers in the presence of cofactors, which are functionally relevant. Our simulations show that the preferred oligomeric assembly is dependent on the binding partners and on the type of severing protein. Essential dynamics analysis predicts that the stability of an oligomer is dependent on the strength of the interface between the helical bundle domain (HBD) of a monomer and the convex face of the nucleotide binding domain (NBD) of a neighboring monomer. Hot spots analysis found that the region consisting of the HBD tip and the C-terminal (CT) helix is the only common element between the allosteric networks responding to nucleotide, substrate, and intermonomer binding. Clustering analysis indicates the existence of multiple pathways for the transition between the secondary structure of the HBD tip in monomers and the structure(s) it adopts in oligomers.
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Affiliation(s)
- Amanda C Macke
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Maria S Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Rohith Anand Varikoti
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Sarah Mullen
- Department of Chemistry, The College of Wooster, Wooster, Ohio 44691, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Daniel Groves
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Clare Forbes
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
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3
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Wang H, Sun J, Yang F, Weng Y, Chen P, Du S, Wei A, Li Y. CsKTN1 for a katanin p60 subunit is associated with the regulation of fruit elongation in cucumber (Cucumis sativus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:2429-2441. [PMID: 34043036 DOI: 10.1007/s00122-021-03833-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
We identified a short fruit3 (sf3) mutant in cucumber. Map-based cloning revealed that CsKTN1 gene encodes a katanin p60 subunit, which is associated with the regulation of fruit elongation. Fruit length is an important horticultural trait for both fruit yield and quality of cucumber (Cucumis sativus L.). Knowledge on the molecular regulation of fruit elongation in cucumber is very limited. In this study, we identified and characterized a cucumber short fruit3 (sf3) mutant. Histological examination indicated that the shorter fruit in the mutant was due to reduced cell numbers. Genetic analysis revealed that the phenotype of the sf3 mutant was controlled by a single gene with semi-dominant inheritance. By map-based cloning and Arabidopsis genetic transformation, we showed that Sf3 was a homolog of KTN1 (CsKTN1) encoding a katanin p60 subunit. A non-synonymous mutation in the fifth exon of CsKTN1 resulted in an amino acid substitution from Serine in the wild type to Phenylalanine in the sf3 mutant. CsKTN1 expressed in all tissues of both the wild type and the sf3 mutant. However, there was no significant difference in CsKTN1 expression levels between the wild type and the sf3 mutant. The hormone quantitation and RNA-seq analysis suggested that auxin and gibberellin contents are decreased in sf3 by changing the expression levels of genes related with auxin and gibberellin metabolism and signaling. This work helps understand the function of the katanin and the molecular mechanisms of fruit growth regulation in cucumber.
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Affiliation(s)
- Hui Wang
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jing Sun
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Fan Yang
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yiqun Weng
- Horticulture Department, USDA-ARS Vegetable Crops Research Unit, University of Wisconsin, Madison, WI, 53706, USA
| | - Peng Chen
- College of Life Science, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Shengli Du
- Tianjin Vegetable Research Center, Tianjin, 300192, China
- National Key Laboratory of Vegetable Germplasm Innovation, Tianjin, 300192, China
| | - Aimin Wei
- Tianjin Vegetable Research Center, Tianjin, 300192, China.
- National Key Laboratory of Vegetable Germplasm Innovation, Tianjin, 300192, China.
| | - Yuhong Li
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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4
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Schneider R, Klooster KV, Picard KL, van der Gucht J, Demura T, Janson M, Sampathkumar A, Deinum EE, Ketelaar T, Persson S. Long-term single-cell imaging and simulations of microtubules reveal principles behind wall patterning during proto-xylem development. Nat Commun 2021; 12:669. [PMID: 33510146 PMCID: PMC7843992 DOI: 10.1038/s41467-021-20894-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/22/2020] [Indexed: 01/23/2023] Open
Abstract
Plants are the tallest organisms on Earth; a feature sustained by solute-transporting xylem vessels in the plant vasculature. The xylem vessels are supported by strong cell walls that are assembled in intricate patterns. Cortical microtubules direct wall deposition and need to rapidly re-organize during xylem cell development. Here, we establish long-term live-cell imaging of single Arabidopsis cells undergoing proto-xylem trans-differentiation, resulting in spiral wall patterns, to understand microtubule re-organization. We find that the re-organization requires local microtubule de-stabilization in band-interspersing gaps. Using microtubule simulations, we recapitulate the process in silico and predict that spatio-temporal control of microtubule nucleation is critical for pattern formation, which we confirm in vivo. By combining simulations and live-cell imaging we further explain how the xylem wall-deficient and microtubule-severing KATANIN contributes to microtubule and wall patterning. Hence, by combining quantitative microscopy and modelling we devise a framework to understand how microtubule re-organization supports wall patterning. Plant cell wall formation is directed by cortical microtubules, which produce complex patterns needed to support xylem vessels. Here, the authors perform live-cell imaging and simulations of Arabidopsis cells during proto-xylem differentiation to show how local microtubule dynamics control pattern formation.
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Affiliation(s)
- René Schneider
- School of Biosciences, University of Melbourne, Parkville, VIC, 3010, Australia.,Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Kris Van't Klooster
- Laboratory of Cell Biology, Wageningen University, Wageningen, The Netherlands.,Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - Kelsey L Picard
- School of Biosciences, University of Melbourne, Parkville, VIC, 3010, Australia.,School of Natural Sciences, University of Tasmania, Hobart, 7001, TAS, Australia
| | - Jasper van der Gucht
- Physical Chemistry and Soft Matter, Wageningen University, Wageningen, The Netherlands
| | - Taku Demura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Marcel Janson
- Laboratory of Cell Biology, Wageningen University, Wageningen, The Netherlands
| | - Arun Sampathkumar
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Eva E Deinum
- Mathematical and Statistical Methods (Biometris), Wageningen University, Wageningen, The Netherlands.
| | - Tijs Ketelaar
- Laboratory of Cell Biology, Wageningen University, Wageningen, The Netherlands.
| | - Staffan Persson
- School of Biosciences, University of Melbourne, Parkville, VIC, 3010, Australia. .,Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark. .,Copenhagen Plant Science Center, University of Copenhagen, 1871, Frederiksberg C, Denmark. .,Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
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5
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Ovečka M, Luptovčiak I, Komis G, Šamajová O, Samakovli D, Šamaj J. Spatiotemporal Pattern of Ectopic Cell Divisions Contribute to Mis-Shaped Phenotype of Primary and Lateral Roots of katanin1 Mutant. FRONTIERS IN PLANT SCIENCE 2020; 11:734. [PMID: 32582258 PMCID: PMC7296145 DOI: 10.3389/fpls.2020.00734] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/07/2020] [Indexed: 05/04/2023]
Abstract
Pattern formation, cell proliferation, and directional cell growth, are driving factors of plant organ shape, size, and overall vegetative development. The establishment of vegetative morphogenesis strongly depends on spatiotemporal control and synchronization of formative and proliferative cell division patterns. In this context, the progression of cell division and the regulation of cell division plane orientation are defined by molecular mechanisms converging to the proper positioning and temporal reorganization of microtubule arrays such as the preprophase microtubule band, the mitotic spindle and the cytokinetic phragmoplast. By focusing on the tractable example of primary root development and lateral root emergence in Arabidopsis thaliana, genetic studies have highlighted the importance of mechanisms underlying microtubule reorganization in the establishment of the root system. In this regard, severe alterations of root growth, and development found in extensively studied katanin1 mutants of A. thaliana (fra2, lue1, and ktn1-2), were previously attributed to defective rearrangements of cortical microtubules and aberrant cell division plane reorientation. How KATANIN1-mediated microtubule severing contributes to tissue patterning and organ morphogenesis, ultimately leading to anisotropy in microtubule organization is a trending topic under vigorous investigation. Here we addressed this issue during root development, using advanced light-sheet fluorescence microscopy (LSFM) and long-term imaging of ktn1-2 mutant expressing the GFP-TUA6 microtubule marker. This method allowed spatial and temporal monitoring of cell division patterns in growing roots. Analysis of acquired multidimensional data sets revealed the occurrence of ectopic cell divisions in various tissues including the calyptrogen and the protoxylem of the main root, as well as in lateral root primordia. Notably the ktn1-2 mutant exhibited excessive longitudinal cell divisions (parallel to the root axis) at ectopic positions. This suggested that changes in the cell division pattern and the occurrence of ectopic cell divisions contributed significantly to pleiotropic root phenotypes of ktn1-2 mutant. LSFM provided evidence that KATANIN1 is required for the spatiotemporal control of cell divisions and establishment of tissue patterns in living A. thaliana roots.
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6
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Wang C, Liu W, Wang G, Li J, Dong L, Han L, Wang Q, Tian J, Yu Y, Gao C, Kong Z. KTN80 confers precision to microtubule severing by specific targeting of katanin complexes in plant cells. EMBO J 2017; 36:3435-3447. [PMID: 28978669 DOI: 10.15252/embj.201796823] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 08/31/2017] [Accepted: 09/08/2017] [Indexed: 11/09/2022] Open
Abstract
The microtubule (MT)-severing enzyme katanin triggers dynamic reorientation of cortical MT arrays that play crucial functions during plant cell morphogenesis, such as cell elongation, cell wall biosynthesis, and hormonal signaling. MT severing specifically occurs at crossover or branching nucleation sites in living Arabidopsis cells. This differs from the random severing observed along the entire length of single MTs in vitro and strongly suggests that a precise control mechanism must exist in vivo However, how katanin senses and cleaves at MT crossover and branching nucleation sites in vivo has remained unknown. Here, we show that the katanin p80 subunit KTN80 confers precision to MT severing by specific targeting of the katanin p60 subunit KTN1 to MT cleavage sites and that KTN1 is required for oligomerization of functional KTN80-KTN1 complexes that catalyze severing. Moreover, our findings suggest that the katanin complex in Arabidopsis is composed of a hexamer of KTN1-KTN80 heterodimers that sense MT geometry to confer precise MT severing. Our findings shed light on the precise control mechanism of MT severing in plant cells, which may be relevant for other eukaryotes.
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Affiliation(s)
- Chaofeng Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Weiwei Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jun Li
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Li Dong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Libo Han
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qi Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Juan Tian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Caixia Gao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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7
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Takáč T, Šamajová O, Pechan T, Luptovčiak I, Šamaj J. Feedback Microtubule Control and Microtubule-Actin Cross-talk in Arabidopsis Revealed by Integrative Proteomic and Cell Biology Analysis of KATANIN 1 Mutants. Mol Cell Proteomics 2017; 16:1591-1609. [PMID: 28706004 DOI: 10.1074/mcp.m117.068015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/06/2017] [Indexed: 12/20/2022] Open
Abstract
Microtubule organization and dynamics are critical for key developmental processes such as cell division, elongation, and morphogenesis. Microtubule severing is an essential regulator of microtubules and is exclusively executed by KATANIN 1 in Arabidopsis In this study, we comparatively studied the proteome-wide effects in two KATANIN 1 mutants. Thus, shotgun proteomic analysis of roots and aerial parts of single nucleotide mutant fra2 and T-DNA insertion mutant ktn1-2 was carried out. We have detected 42 proteins differentially abundant in both fra2 and ktn1-2 KATANIN 1 dysfunction altered the abundance of proteins involved in development, metabolism, and stress responses. The differential regulation of tubulins and microtubule-destabilizing protein MDP25 implied a feedback microtubule control in KATANIN 1 mutants. Furthermore, deregulation of profilin 1, actin-depolymerizing factor 3, and actin 7 was observed. These findings were confirmed by immunoblotting analysis of actin and by microscopic observation of actin filaments using fluorescently labeled phalloidin. Results obtained by quantitative RT-PCR analysis revealed that changed protein abundances were not a consequence of altered expression levels of corresponding genes in the mutants. In conclusion, we show that abundances of several cytoskeletal proteins as well as organization of microtubules and the actin cytoskeleton are amended in accordance with defective microtubule severing.
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Affiliation(s)
- Tomáš Takáč
- From the ‡Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Olga Šamajová
- From the ‡Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Tibor Pechan
- §Institute for Genomics, Biocomputing and Biotechnology, Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Starkville, Mississippi 39759
| | - Ivan Luptovčiak
- From the ‡Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jozef Šamaj
- From the ‡Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic;
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8
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Bailey ME, Jiang N, Dima RI, Ross JL. Invited review: Microtubule severing enzymes couple atpase activity with tubulin GTPase spring loading. Biopolymers 2017; 105:547-56. [PMID: 27037673 DOI: 10.1002/bip.22842] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/23/2016] [Accepted: 03/28/2016] [Indexed: 12/21/2022]
Abstract
Microtubules are amazing filaments made of GTPase enzymes that store energy used for their own self-destruction to cause a stochastically driven dynamics called dynamic instability. Dynamic instability can be reproduced in vitro with purified tubulin, but the dynamics do not mimic that observed in cells. This is because stabilizers and destabilizers act to alter microtubule dynamics. One interesting and understudied class of destabilizers consists of the microtubule-severing enzymes from the ATPases Associated with various cellular Activities (AAA+) family of ATP-enzymes. Here we review current knowledge about GTP-driven microtubule dynamics and how that couples to ATP-driven destabilization by severing enzymes. We present a list of challenges regarding the mechanism of severing, which require development of experimental and modeling approaches to shed light as to how severing enzymes can act to regulate microtubule dynamics in cells. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 547-556, 2016.
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Affiliation(s)
- Megan E Bailey
- Department of Physiology and Biophysics, 1705 NE Pacific St., Seattle, WA 98195
| | - Nan Jiang
- Department of Chemistry, University of Cincinnati, Cincinnati OH 45221
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati OH 45221
| | - Jennifer L Ross
- Department of Physics, 666 N. Pleasant St. University of Massachusetts, Amherst, MA 01003
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9
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Luptovčiak I, Komis G, Takáč T, Ovečka M, Šamaj J. Katanin: A Sword Cutting Microtubules for Cellular, Developmental, and Physiological Purposes. FRONTIERS IN PLANT SCIENCE 2017; 8:1982. [PMID: 29209346 PMCID: PMC5702333 DOI: 10.3389/fpls.2017.01982] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/03/2017] [Indexed: 05/02/2023]
Abstract
KATANIN is a well-studied microtubule severing protein affecting microtubule organization and dynamic properties in higher plants. By regulating mitotic and cytokinetic and cortical microtubule arrays it is involved in the progression of cell division and cell division plane orientation. KATANIN is also involved in cell elongation and morphogenesis during plant growth. In this way KATANIN plays critical roles in diverse plant developmental processes including the development of pollen, embryo, seed, meristem, root, hypocotyl, cotyledon, leaf, shoot, and silique. KATANIN-dependent microtubule regulation seems to be under the control of plant hormones. This minireview provides an overview on available KATANIN mutants and discusses advances in our understanding of KATANIN biological roles in plants.
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10
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Luptovčiak I, Samakovli D, Komis G, Šamaj J. KATANIN 1 Is Essential for Embryogenesis and Seed Formation in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2017; 8:728. [PMID: 28529520 PMCID: PMC5418335 DOI: 10.3389/fpls.2017.00728] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/19/2017] [Indexed: 05/10/2023]
Abstract
Cytoskeletal remodeling has a fundamental role, especially during transitional developmental stages when cells rapidly adopt new forms and roles, like gametogenesis, fertilization and concomitant embryogenesis and seed formation. KATANIN 1, a microtubule severing protein, fulfills a major regulatory mechanism of dynamic microtubule turnover in eukaryotes. Herein, we show that three well-established KATANIN 1 mutants, fra2, lue1 and ktn1-2 collectively display lower fertility and seed set in Arabidopsis. These lower fertility and seed set rates of fra2, lue1 and ktn1-2 mutants were correlated to abnormalities in the development of embryo proper and seed. Such phenotypes were rescued by transformation of mutants with functional pKTN1::GFP:KTN1 construct. This study significantly expands the already broad functional repertoire of KATANIN 1 and unravels its new role in embryo and seed development. Thus, KATANIN 1 significantly contributes to the fertility and proper embryo and seed formation in Arabidopsis.
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11
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Grode KD, Rogers SL. The non-catalytic domains of Drosophila katanin regulate its abundance and microtubule-disassembly activity. PLoS One 2015; 10:e0123912. [PMID: 25886649 PMCID: PMC4401518 DOI: 10.1371/journal.pone.0123912] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/24/2015] [Indexed: 01/07/2023] Open
Abstract
Microtubule severing is a biochemical reaction that generates an internal break in a microtubule and regulation of microtubule severing is critical for cellular processes such as ciliogenesis, morphogenesis, and meiosis and mitosis. Katanin is a conserved heterodimeric ATPase that severs and disassembles microtubules, but the molecular determinants for regulation of microtubule severing by katanin remain poorly defined. Here we show that the non-catalytic domains of Drosophila katanin regulate its abundance and activity in living cells. Our data indicate that the microtubule-interacting and trafficking (MIT) domain and adjacent linker region of the Drosophila katanin catalytic subunit Kat60 cooperate to regulate microtubule severing in two distinct ways. First, the MIT domain and linker region of Kat60 decrease its abundance by enhancing its proteasome-dependent degradation. The Drosophila katanin regulatory subunit Kat80, which is required to stabilize Kat60 in cells, conversely reduces the proteasome-dependent degradation of Kat60. Second, the MIT domain and linker region of Kat60 augment its microtubule-disassembly activity by enhancing its association with microtubules. On the basis of our data, we propose that the non-catalytic domains of Drosophila katanin serve as the principal sites of integration of regulatory inputs, thereby controlling its ability to sever and disassemble microtubules.
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Affiliation(s)
- Kyle D. Grode
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Stephen L. Rogers
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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12
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Chou WL, Huang LF, Fang JC, Yeh CH, Hong CY, Wu SJ, Lu CA. Divergence of the expression and subcellular localization of CCR4-associated factor 1 (CAF1) deadenylase proteins in Oryza sativa. PLANT MOLECULAR BIOLOGY 2014; 85:443-58. [PMID: 24805883 DOI: 10.1007/s11103-014-0196-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 04/25/2014] [Indexed: 05/27/2023]
Abstract
Deadenylation, also called poly(A) tail shortening, is the first, rate-limiting step in the general cytoplasmic mRNA degradation in eukaryotic cells. The CCR4-NOT complex, containing the two key components carbon catabolite repressor 4 (CCR4) and CCR4-associated factor 1 (CAF1), is a major player in deadenylation. CAF1 belongs to the RNase D group in the DEDD superfamily, and is a protein conserved through evolution from yeast to humans and plants. Every higher plant, including Arabidopsis and rice, contains a CAF1 multigene family. In this study, we identified and cloned four OsCAF1 genes (OsCAF1A, OsCAF1B, OsCAF1G, and OsCAF1H) from rice. Four recombinant OsCAF1 proteins, rOsCAF1A, rOsCAF1B, rOsCAF1G, and rOsCAF1H, all exhibited 3'-5' exonuclease activity in vitro. Point mutations in the catalytic residues of each analyzed recombinant OsCAF1 proteins were shown to disrupt deadenylase activity. OsCAF1A and OsCAF1G mRNA were found to be abundant in the leaves of mature plants. Two types of OsCAF1B mRNA transcript were detected in an inverse expression pattern in various tissues. OsCAF1B was transient, induced by drought, cold, abscisic acid, and wounding treatments. OsCAF1H mRNA was not detected either under normal conditions or during most stress treatments, but only accumulated during heat stress. Four OsCAF1-reporter fusion proteins were localized in both the cytoplasm and nucleus. In addition, when green fluorescent protein fused with OsCAF1B, OsCAF1G, and OsCAF1H, respectively, fluorescent spots were observed in the nucleolus. OsCAF1B fluorescent fusion proteins were located in discrete cytoplasmic foci and fibers. We present evidences that OsCAF1B colocalizes with AtXRN4, a processing body marker, and AtKSS12, a microtubules maker, indicating that OsCAF1B is a component of the plant P-body and associate with microtubules. Our findings provide biochemical evidence that OsCAF1 proteins may be involved in the deadenylation in rice. The unique expression patterns of each OsCAF1 were observed in various tissues when undergoing abiotic stress treatments, implying that each CAF1 gene in rice plays a specific role in the development and stress response of a plant.
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Affiliation(s)
- Wei-Lun Chou
- Department of Life Sciences, National Central University, Jhongli City, Taoyuan County, 320, Taiwan, ROC
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13
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Komis G, Mistrik M, Šamajová O, Doskočilová A, Ovečka M, Illés P, Bartek J, Šamaj J. Dynamics and organization of cortical microtubules as revealed by superresolution structured illumination microscopy. PLANT PHYSIOLOGY 2014; 165:129-48. [PMID: 24686112 PMCID: PMC4012574 DOI: 10.1104/pp.114.238477] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/28/2014] [Indexed: 05/07/2023]
Abstract
Plants employ acentrosomal mechanisms to organize cortical microtubule arrays essential for cell growth and differentiation. Using structured illumination microscopy (SIM) adopted for the optimal documentation of Arabidopsis (Arabidopsis thaliana) hypocotyl epidermal cells, dynamic cortical microtubules labeled with green fluorescent protein fused to the microtubule-binding domain of the mammalian microtubule-associated protein MAP4 and with green fluorescent protein-fused to the alpha tubulin6 were comparatively recorded in wild-type Arabidopsis plants and in the mitogen-activated protein kinase mutant mpk4 possessing the former microtubule marker. The mpk4 mutant exhibits extensive microtubule bundling, due to increased abundance and reduced phosphorylation of the microtubule-associated protein MAP65-1, thus providing a very useful genetic tool to record intrabundle microtubule dynamics at the subdiffraction level. SIM imaging revealed nano-sized defects in microtubule bundling, spatially resolved microtubule branching and release, and finally allowed the quantification of individual microtubules within cortical bundles. Time-lapse SIM imaging allowed the visualization of subdiffraction, short-lived excursions of the microtubule plus end, and dynamic instability behavior of both ends during free, intrabundle, or microtubule-templated microtubule growth and shrinkage. Finally, short, rigid, and nondynamic microtubule bundles in the mpk4 mutant were observed to glide along the parent microtubule in a tip-wise manner. In conclusion, this study demonstrates the potential of SIM for superresolution time-lapse imaging of plant cells, showing unprecedented details accompanying microtubule dynamic organization.
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Affiliation(s)
- George Komis
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Martin Mistrik
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Olga Šamajová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Anna Doskočilová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Miroslav Ovečka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Peter Illés
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
| | - Jiri Bartek
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University Olomouc, 783 71 Olomouc, Czech Republic (G.K., O.Š., A.D., M.O., P.I., J.Š.)
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, 779 00 Olomouc, Czech Republic (M.M., J.B.); and
- Danish Cancer Society Research Center, DK–2100 Copenhagen, Denmark (J.B.)
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McNally K, Berg E, Cortes DB, Hernandez V, Mains PE, McNally FJ. Katanin maintains meiotic metaphase chromosome alignment and spindle structure in vivo and has multiple effects on microtubules in vitro. Mol Biol Cell 2014; 25:1037-49. [PMID: 24501424 PMCID: PMC3967969 DOI: 10.1091/mbc.e13-12-0764] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Caenorhabditis elegans bivalents are positioned between dense bundles of microtubules within female meiotic spindles. Rapid inactivation of katanin after meiotic spindle assembly causes loss of organized microtubule bundles and displacement of bivalents from the metaphase plate. Purified katanin can preferentially sever at intersections between microtubules. Assembly of Caenorhabditis elegans female meiotic spindles requires both MEI-1 and MEI-2 subunits of the microtubule-severing ATPase katanin. Strong loss-of-function mutants assemble apolar intersecting microtubule arrays, whereas weaker mutants assemble bipolar meiotic spindles that are longer than wild type. To determine whether katanin is also required for spindle maintenance, we monitored metaphase I spindles after a fast-acting mei-1(ts) mutant was shifted to a nonpermissive temperature. Within 4 min of temperature shift, bivalents moved off the metaphase plate, and microtubule bundles within the spindle lengthened and developed a high degree of curvature. Spindles eventually lost bipolar structure. Immunofluorescence of embryos fixed at increasing temperature indicated that MEI-1 was lost from spindle microtubules before loss of ASPM-1, indicating that MEI-1 and ASPM-1 act independently at spindle poles. We quantified the microtubule-severing activity of purified MEI-1/MEI-2 complexes corresponding to six different point mutations and found a linear relationship between microtubule disassembly rate and meiotic spindle length. Previous work showed that katanin is required for severing at points where two microtubules intersect in vivo. We show that purified MEI-1/MEI-2 complexes preferentially sever at intersections between two microtubules and directly bundle microtubules in vitro. These activities could promote parallel/antiparallel microtubule organization in meiotic spindles.
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Affiliation(s)
- Karen McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616 Genes and Development Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
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15
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Microtubule Severing at Crossover Sites by Katanin Generates Ordered Cortical Microtubule Arrays in Arabidopsis. Curr Biol 2013; 23:2191-5. [DOI: 10.1016/j.cub.2013.09.018] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/29/2013] [Accepted: 09/09/2013] [Indexed: 11/23/2022]
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16
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Gardiner J. The evolution and diversification of plant microtubule-associated proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:219-29. [PMID: 23551562 DOI: 10.1111/tpj.12189] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 03/11/2013] [Accepted: 03/22/2013] [Indexed: 05/07/2023]
Abstract
Plant evolution is marked by major advances in structural characteristics that facilitated the highly successful colonization of dry land. Underlying these advances is the evolution of genes encoding specialized proteins that form novel microtubular arrays of the cytoskeleton. This review investigates the evolution of plant families of microtubule-associated proteins (MAPs) through the recently sequenced genomes of Arabidopsis thaliana, Oryza sativa, Selaginella moellendorffii, Physcomitrella patens, Volvox carteri and Chlamydomonas reinhardtii. The families of MAPs examined are AIR9, CLASP, CRIPT, MAP18, MOR1, TON, EB1, AtMAP70, SPR2, SPR1, WVD2 and MAP65 families (abbreviations are defined in the footnote to Table 1). Conjectures are made regarding the evolution of MAPs in plants in relation to the evolution of multicellularity, oriented cell division and vasculature. Angiosperms in particular have high numbers of proteins that are involved in promotion of helical growth or its suppression, and novel plant microtubular structures may have acted as a catalyst for the development of novel plant MAPs. Comparisons of plant MAP gene families with those of animals show that animals may have more flexibility in the structure of their microtubule cytoskeletons than plants, but with both plants and animals possessing many MAP splice variants.
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Affiliation(s)
- John Gardiner
- School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
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17
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Eckert T, Le DTV, Link S, Friedmann L, Woehlke G. Spastin's microtubule-binding properties and comparison to katanin. PLoS One 2012; 7:e50161. [PMID: 23272056 PMCID: PMC3521757 DOI: 10.1371/journal.pone.0050161] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/17/2012] [Indexed: 11/19/2022] Open
Abstract
Spastin and katanin are ring-shaped hexameric AAA ATPases that sever microtubules, and thus crucially depend on a physical interaction with microtubules. For the first time, we report here the microtubule binding properties of spastin at the single-molecule level, and compare them to katanin. Microscopic fluorescence assays showed that human spastin bound to microtubules by ionic interactions, and diffused along microtubules with a diffusion coefficient comparable to katanin. The microscopic measurement of landing and dissociation rates demonstrated the ionic character of the interaction, which could be mapped to a patch of three lysine residues outside of the catalytic domain of human spastin. This motif is not conserved in Drosophila spastin or katanin, which also bound by non-catalytic parts of the protein. The binding affinities of spastin and katanin were nucleotide-sensitive, with the lowest affinities under ADP,, the highest under ATP-γS conditions. These changes correlated with the formation of higher oligomeric states, as shown in biochemical experiments and electron microscopic images. Vice versa, the artificial dimerization of human spastin by addition of a coiled coil led to a constitutively active enzyme. These observations suggest that dimer formation is a crucial step in the formation of the active complex, and thus the severing process by spastin.
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Affiliation(s)
| | | | | | | | - Günther Woehlke
- Department of Physics E22 (Biophysics), Technische Universität München, Garching, Germany
- * E-mail:
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18
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Krtková J, Zimmermann A, Schwarzerová K, Nick P. Hsp90 binds microtubules and is involved in the reorganization of the microtubular network in angiosperms. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1329-39. [PMID: 22840326 DOI: 10.1016/j.jplph.2012.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/14/2012] [Accepted: 06/15/2012] [Indexed: 05/13/2023]
Abstract
Microtubules (MTs) are essential for many processes in plant cells. MT-associated proteins (MAPs) influence MT polymerization dynamics and enable them to perform their functions. The molecular chaperone Hsp90 has been shown to associate with MTs in animal and plant cells. However, the role of Hsp90-MT binding in plants has not yet been investigated. Here, we show that Hsp90 associates with cortical MTs in tobacco cells and decorates MTs in the phragmoplast. Further, we show that tobacco Hsp90_MT binds directly to polymerized MTs in vitro. The inhibition of Hsp90 by geldanamycin (GDA) severely impairs MT re-assembly after cold-induced de-polymerization. Our results indicate that the plant Hsp90 interaction with MTs plays a key role in cellular events, where MT re-organization is needed.
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Affiliation(s)
- Jana Krtková
- Department of Experimental Plant Biology, Charles University in Prague, Viničná 5, 128 44 Prague 2, Czech Republic.
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19
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Zach F, Grassmann F, Langmann T, Sorusch N, Wolfrum U, Stöhr H. The retinitis pigmentosa 28 protein FAM161A is a novel ciliary protein involved in intermolecular protein interaction and microtubule association. Hum Mol Genet 2012; 21:4573-86. [PMID: 22791751 DOI: 10.1093/hmg/dds268] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Loss-of-function mutations in the gene encoding FAM161A were recently discovered as the cause for RP28, an autosomal recessive form of retinitis pigmentosa. To initiate the characterization of the cellular role of FAM161A in the retina, we focused on its subcellular localization and conducted in vitro studies to identify FAM161A-interacting proteins and associated cellular structures. Immunohistochemistry revealed the presence of mouse FAM161A in the photoreceptor inner segments, the synaptic regions of the outer and inner plexiform layers and the ganglion cells. In mouse and human retinal sections from unfixed eyes, FAM161A localized to the ciliary region linking photoreceptor outer and inner segments. High-resolution immunofluorescence and immunoelectron microscopy mapped FAM161A to the connecting cilium, the basal body region and the adjacent centriole. Ectopic FAM161A was found in the centrosome and concentrated at the base of primary cilia in cultured cells. In addition, overexpressed FAM161A was clearly associated with microtubules during interphase and mitosis. The presence of FAM161A increased microtubule acetylation and stabilization. We further show that the evolutionarily conserved UPF0564 domain of FAM161A is crucial for its binding to microtubules and mediates homo- and heterotypic FAM161A and FAM161B interaction. In conclusion, our study shows that FAM161A is a microtubule-associated ciliary protein presumably involved in microtubule stabilization to maintain the microtubule tracks and/or in transport processes along microtubules in photoreceptors and other retinal cell types.
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Affiliation(s)
- Frank Zach
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
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20
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Dymek EE, Smith EF. PF19 encodes the p60 catalytic subunit of katanin and is required for assembly of the flagellar central apparatus in Chlamydomonas. J Cell Sci 2012; 125:3357-66. [PMID: 22467860 DOI: 10.1242/jcs.096941] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For all eukaryotic cilia the basal bodies provide a template for the assembly of the doublet microtubules, and intraflagellar transport provides a mechanism for transport of axonemal components into the growing cilium. What is not known is how the central pair of microtubules is nucleated or how their associated polypeptides are assembled. Here we report that the Chlamydomonas pf19 mutation results in a single amino acid change within the p60 catalytic subunit of katanin, and that this mutation prevents microtubule severing activity. The pf19 mutant has paralyzed flagella that lack the central apparatus. Using a combination of mutant analysis, RNAi-mediated reduction of protein expression and in vitro assays, we demonstrate that the p60 catalytic subunit of the microtubule severing protein katanin is required for central apparatus assembly in Chlamydomonas. In addition, we show that in Chlamydomonas the microtubule severing activity of p60 katanin is not required for stress-induced deflagellation or cell cycle progression as has been previously reported.
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Affiliation(s)
- Erin E Dymek
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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21
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Drosophila katanin is a microtubule depolymerase that regulates cortical-microtubule plus-end interactions and cell migration. Nat Cell Biol 2011; 13:361-70. [PMID: 21378981 DOI: 10.1038/ncb2206] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 01/07/2011] [Indexed: 01/06/2023]
Abstract
Regulation of microtubule dynamics at the cell cortex is important for cell motility, morphogenesis and division. Here we show that the Drosophila katanin Dm-Kat60 functions to generate a dynamic cortical-microtubule interface in interphase cells. Dm-Kat60 concentrates at the cell cortex of S2 Drosophila cells during interphase, where it suppresses the polymerization of microtubule plus-ends, thereby preventing the formation of aberrantly dense cortical arrays. Dm-Kat60 also localizes at the leading edge of migratory D17 Drosophila cells and negatively regulates multiple parameters of their motility. Finally, in vitro, Dm-Kat60 severs and depolymerizes microtubules from their ends. On the basis of these data, we propose that Dm-Kat60 removes tubulin from microtubule lattice or microtubule ends that contact specific cortical sites to prevent stable and/or lateral attachments. The asymmetric distribution of such an activity could help generate regional variations in microtubule behaviours involved in cell migration.
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22
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McNally KP, McNally FJ. The spindle assembly function of Caenorhabditis elegans katanin does not require microtubule-severing activity. Mol Biol Cell 2011; 22:1550-60. [PMID: 21372175 PMCID: PMC3084677 DOI: 10.1091/mbc.e10-12-0951] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Katanin is a heterodimeric microtubule-severing protein that is conserved among eukaryotes. Loss-of-function mutations in the Caenorhabditis elegans katanin catalytic subunit, MEI-1, cause specific defects in female meiotic spindles. To determine the relationship between katanin's microtubule-severing activity and its role in meiotic spindle formation, we analyzed the MEI-1(A338S) mutant. Unlike wild-type MEI-1, which mediated disassembly of microtubule arrays in Xenopus fibroblasts, MEI-1(A338S) had no effect on fibroblast microtubules, indicating a lack of microtubule-severing activity. In C. elegans, MEI-1(A338S) mediated assembly of extremely long bipolar meiotic spindles. In contrast, a nonsense mutation in MEI-1 caused assembly of meiotic spindles without any poles as assayed by localization of the spindle-pole protein, ASPM-1. These results indicated that katanin protein, but not katanin's microtubule-severing activity, is required for assembly of acentriolar meiotic spindle poles. To understand the nonsevering activities of katanin, we characterized the N-terminal domain of the katanin catalytic subunit. The N-terminal domain was necessary and sufficient for binding to the katanin regulatory subunit. The katanin regulatory subunit in turn caused a dramatic change in the microtubule-binding properties of the N-terminal domain of the catalytic subunit. This unique bipartite microtubule-binding structure may mediate the spindle-pole assembly activity of katanin during female meiosis.
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Affiliation(s)
- Karen Perry McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
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23
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Keech O, Pesquet E, Gutierrez L, Ahad A, Bellini C, Smith SM, Gardeström P. Leaf senescence is accompanied by an early disruption of the microtubule network in Arabidopsis. PLANT PHYSIOLOGY 2010; 154:1710-20. [PMID: 20966154 PMCID: PMC2996031 DOI: 10.1104/pp.110.163402] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Accepted: 10/18/2010] [Indexed: 05/18/2023]
Abstract
The dynamic assembly and disassembly of microtubules (MTs) is essential for cell function. Although leaf senescence is a well-documented process, the role of the MT cytoskeleton during senescence in plants remains unknown. Here, we show that both natural leaf senescence and senescence of individually darkened Arabidopsis (Arabidopsis thaliana) leaves are accompanied by early degradation of the MT network in epidermis and mesophyll cells, whereas guard cells, which do not senesce, retain their MT network. Similarly, entirely darkened plants, which do not senesce, retain their MT network. While genes encoding the tubulin subunits and the bundling/stabilizing MT-associated proteins (MAPs) MAP65 and MAP70-1 were repressed in both natural senescence and dark-induced senescence, we found strong induction of the gene encoding the MT-destabilizing protein MAP18. However, induction of MAP18 gene expression was also observed in leaves from entirely darkened plants, showing that its expression is not sufficient to induce MT disassembly and is more likely to be part of a Ca(2+)-dependent signaling mechanism. Similarly, genes encoding the MT-severing protein katanin p60 and two of the four putative regulatory katanin p80s were repressed in the dark, but their expression did not correlate with degradation of the MT network during leaf senescence. Taken together, these results highlight the earliness of the degradation of the cortical MT array during leaf senescence and lead us to propose a model in which suppression of tubulin and MAP genes together with induction of MAP18 play key roles in MT disassembly during senescence.
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Affiliation(s)
- Olivier Keech
- Australian Research Council Centre of Excellence in Plant Energy Biology and Centre of Excellence for Plant Metabolomics, University of Western Australia, Crawley, Western Australia 6009, Australia.
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24
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Meng Q, Du J, Li J, Lü X, Zeng X, Yuan M, Mao T. Tobacco microtubule-associated protein, MAP65-1c, bundles and stabilizes microtubules. PLANT MOLECULAR BIOLOGY 2010; 74:537-47. [PMID: 20878450 DOI: 10.1007/s11103-010-9694-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Accepted: 09/16/2010] [Indexed: 05/29/2023]
Abstract
Three genes that encode MAP65-1 family proteins have been identified in the Nicotiana tabacum genome. In this study, NtMAP65-1c fusion protein was shown to bind and bundle microtubules (MTs). Further in vitro investigations demonstrated that NtMAP65-1c not only alters MT assembly and nucleation, but also exhibits high MT stabilizing activity against cold or katanin-induced destabilization. Analysis of NtMAP65-1c-GFP expressing BY-2 cells clearly demonstrated that NtMAP65-1c was able to bind to MTs during specific stages of the cell cycle. Furthermore, in vivo, NtMAP65-1c-GFP-bound cortical MTs displayed an increase in resistance against the MT-disrupting drug, propyzamide, as well as against cold temperatures. Taken together, these results strongly suggest that NtMAP65-1c stabilizes MTs and is involved in the regulation of MT organization and cellular dynamics.
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Affiliation(s)
- Qiutao Meng
- State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
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25
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Iwaya N, Kuwahara Y, Fujiwara Y, Goda N, Tenno T, Akiyama K, Mase S, Tochio H, Ikegami T, Shirakawa M, Hiroaki H. A common substrate recognition mode conserved between katanin p60 and VPS4 governs microtubule severing and membrane skeleton reorganization. J Biol Chem 2010; 285:16822-9. [PMID: 20339000 DOI: 10.1074/jbc.m110.108365] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Katanin p60 (kp60), a microtubule-severing enzyme, plays a key role in cytoskeletal reorganization during various cellular events in an ATP-dependent manner. We show that a single domain isolated from the N terminus of mouse katanin p60 (kp60-NTD) binds to tubulin. The solution structure of kp60-NTD was determined by NMR. Although their sequence similarities were as low as 20%, the structure of kp60-NTD revealed a striking similarity to those of the microtubule interacting and trafficking (MIT) domains, which adopt anti-parallel three-stranded helix bundle. In particular, the arrangement of helices 2 and 3 is well conserved between kp60-NTD and the MIT domain from Vps4, which is a homologous protein that promotes disassembly of the endosomal sorting complexes required for transport III membrane skeleton complex. Mutation studies revealed that the positively charged surface formed by helices 2 and 3 binds tubulin. This binding mode resembles the interaction between the MIT domain of Vps4 and Vps2/CHMP1a, a component of endosomal sorting complexes required for transport III. Our results show that both the molecular architecture and the binding modes are conserved between two AAA-ATPases, kp60 and Vps4. A common mechanism is evolutionarily conserved between two distinct cellular events, one that drives microtubule severing and the other involving membrane skeletal reorganization.
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Affiliation(s)
- Naoko Iwaya
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto 615-8530, Japan
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BARTON D, GARDINER J, OVERALL R. Towards correlative imaging of plant cortical microtubule arrays: combining ultrastructure with real-time microtubule dynamics. J Microsc 2009; 235:241-51. [DOI: 10.1111/j.1365-2818.2009.03224.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Wade RH. On and Around Microtubules: An Overview. Mol Biotechnol 2009; 43:177-91. [DOI: 10.1007/s12033-009-9193-5] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 06/03/2009] [Indexed: 12/31/2022]
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Barton DA, Vantard M, Overall RL. Analysis of cortical arrays from Tradescantia virginiana at high resolution reveals discrete microtubule subpopulations and demonstrates that confocal images of arrays can be misleading. THE PLANT CELL 2008; 20:982-94. [PMID: 18430803 PMCID: PMC2390730 DOI: 10.1105/tpc.108.058503] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/30/2008] [Accepted: 04/07/2008] [Indexed: 05/20/2023]
Abstract
Cortical microtubule arrays are highly organized networks involved in directing cellulose microfibril deposition within the cell wall. Their organization results from complex interactions between individual microtubules and microtubule-associated proteins. The precise details of these interactions are often not evident using optical microscopy. Using high-resolution scanning electron microscopy, we analyzed extensive regions of cortical arrays and identified two spatially discrete microtubule subpopulations that exhibited different stabilities. Microtubules that lay adjacent to the plasma membrane were often bundled and more stable than the randomly aligned, discordant microtubules that lay deeper in the cytoplasm. Immunolabeling revealed katanin at microtubule ends, on curves, or at sites along microtubules in line with neighboring microtubule ends. End binding 1 protein also localized along microtubules, at microtubule ends or junctions between microtubules, and on the plasma membrane in direct line with microtubule ends. We show fine bands in vivo that traverse and may encircle microtubules. Comparing confocal and electron microscope images of fluorescently tagged arrays, we demonstrate that optical images are misleading, highlighting the fundamental importance of studying cortical microtubule arrays at high resolution.
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Affiliation(s)
- Deborah A Barton
- School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
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