1
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Waters ER, Bezanilla M, Vierling E. ATAD3 Proteins: Unique Mitochondrial Proteins Essential for Life in Diverse Eukaryotic Lineages. Plant Cell Physiol 2023:pcad122. [PMID: 37859594 DOI: 10.1093/pcp/pcad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023]
Abstract
ATAD3 proteins (ATPase family AAA domain-containing protein 3) are unique mitochondrial proteins that arose deep in the eukaryotic lineage but that are surprisingly absent from the Fungi and Amoebozoa. These ~600 amino acid proteins are anchored in the inner mitochondrial membrane and are essential in metazoans and Arabidopsis thaliana. ATAD3s comprise a C-terminal AAA+ matrix domain and an ATAD3_N domain that is located primarily in the inner membrane space but potentially extends into cytosol to interact with the ER. Sequence and structural alignments indicate ATAD3 proteins are most similar to classic chaperone unfoldases in AAA+ family, suggesting that they operate in mitochondrial protein quality control. A. thaliana has four ATAD3 genes in two distinct clades that appear first in the seed plants, and both clades are essential for viability. The four genes are generally coordinately expressed, and transcripts are highest in growing apices and imbibed seeds. Plants with disrupted ATAD3 have reduced growth, aberrant mitochondrial morphology, diffuse nucleoids and reduced oxidative phosphorylation complex I. These and other pleiotropic phenotypes are also observed in ATAD3 mutants in metazoans. Here we discuss the distribution of ATAD3 proteins as they have evolved in the plant kingdom, their unique structure, what we know about their function in plants, and the challenges in determining their essential roles in mitochondria.
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Affiliation(s)
- Elizabeth R Waters
- Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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2
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Wu SZ, Chaves AM, Li R, Roberts AW, Bezanilla M. Cellulose synthase-like D movement in the plasma membrane requires enzymatic activity. J Cell Biol 2023; 222:e202212117. [PMID: 37071416 PMCID: PMC10120407 DOI: 10.1083/jcb.202212117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/28/2023] [Accepted: 03/17/2023] [Indexed: 04/19/2023] Open
Abstract
Cellulose Synthase-Like D (CSLD) proteins, important for tip growth and cell division, are known to generate β-1,4-glucan. However, whether they are propelled in the membrane as the glucan chains they produce assemble into microfibrils is unknown. To address this, we endogenously tagged all eight CSLDs in Physcomitrium patens and discovered that they all localize to the apex of tip-growing cells and to the cell plate during cytokinesis. Actin is required to target CSLD to cell tips concomitant with cell expansion, but not to cell plates, which depend on actin and CSLD for structural support. Like Cellulose Synthase (CESA), CSLD requires catalytic activity to move in the plasma membrane. We discovered that CSLD moves significantly faster, with shorter duration and less linear trajectories than CESA. In contrast to CESA, CSLD movement was insensitive to the cellulose synthesis inhibitor isoxaben, suggesting that CSLD and CESA function within different complexes possibly producing structurally distinct cellulose microfibrils.
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Affiliation(s)
- Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Arielle M. Chaves
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
| | - Rongrong Li
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
| | - Alison W. Roberts
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
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3
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Yáñez-Domínguez C, Lagunas-Gómez D, Torres-Cifuentes DM, Bezanilla M, Pantoja O. A cornichon protein controls polar localization of the PINA auxin transporter in Physcomitrium patens. Development 2023; 150:308867. [PMID: 37052186 DOI: 10.1242/dev.201635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Newly synthesized membrane proteins pass through the secretory pathway, starting at the endoplasmic reticulum and packaged into COPII vesicles, to continue to the Golgi apparatus before reaching their membrane of residence. It is known that cargo receptor proteins form part of the COPII complex and play a role in the recruitment of cargo proteins for their subsequent transport through the secretory pathway. The role of cornichon proteins is conserved from yeast to vertebrates, but it is poorly characterized in plants. Here, we studied the role of the two cornichon homologs in the secretory pathway of the moss Physcomitrium patens. Mutant analyzes revealed that cornichon genes regulate different growth processes during the moss life cycle by controlling auxin transport, with CNIH2 functioning as a specific cargo receptor for the auxin efflux carrier PINA, with the C-terminus of the receptor regulating the interaction, trafficking, and membrane localization of PINA.
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Affiliation(s)
- Carolina Yáñez-Domínguez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México, USA
| | - Daniel Lagunas-Gómez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México, USA
| | - Diana Milena Torres-Cifuentes
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México, USA
- Department of Biological Sciences, Dartmouth, Hanover, New Hampshire 03755, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth, Hanover, New Hampshire 03755, USA
| | - Omar Pantoja
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México, USA
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4
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Wu SZ, Ryken SE, Bezanilla M. CRISPR-Cas9 Genome Editing in the Moss Physcomitrium (Formerly Physcomitrella) patens. Curr Protoc 2023; 3:e725. [PMID: 37021953 DOI: 10.1002/cpz1.725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Until recently, precise genome editing has been limited to a few organisms. The ability of Cas9 to generate double stranded DNA breaks at specific genomic sites has greatly expanded molecular toolkits in many organisms and cell types. Before CRISPR-Cas9 mediated genome editing, P. patens was unique among plants in its ability to integrate DNA via homologous recombination. However, selection for homologous recombination events was required to obtain edited plants, limiting the types of editing that were possible. Now with CRISPR-Cas9, molecular manipulations in P. patens have greatly expanded. This protocol describes a method to generate a variety of different genome edits. The protocol describes a streamlined method to generate the Cas9/sgRNA expression constructs, design homology templates, transform, and quickly genotype plants. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Constructing the Cas9/sgRNA transient expression vector Alternate Protocol 1: Shortcut to generating single and pooled Cas9/sgRNA expression vectors Basic Protocol 2: Designing the oligonucleotide-based homology-directed repair (HDR) template Alternate Protocol 2: Designing the plasmid-based HDR template Basic Protocol 3: Inducing genome editing by transforming CRISPR vector into P. patens protoplasts Basic Protocol 4: Identifying edited plants.
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Affiliation(s)
- Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire
| | - Samantha E Ryken
- Current address: Biological and Biomedical Sciences Program, University of North Carolina, Chapel Hill, North Carolina
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire
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5
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Cardon ZG, Peredo EL, Enloe CM, Oakey JS, Wu SZ, Bezanilla M. Slip slidin' away: Bristle-driven gliding by Tetradesmus deserticola (Chlorophyta) in microfluidic chambers. J Phycol 2022; 58:626-630. [PMID: 35608962 DOI: 10.1111/jpy.13271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
Microalgae within the Scenedesmaceae are often distinguished by spines, bristles, and other wall characteristics. We examined the dynamic production and chemical nature of bristles extruded from the poles of Tetradesmus deserticola previously isolated from microbiotic crust. Rapidly growing cells in a liquid growth medium were established in polydimethylsiloxane microfluidic chambers specially designed to maintain aerobic conditions over time within a chamber 6-12 μm deep. This geometry enabled in-focus imaging of single cells over long periods. Differential interference contrast (DIC) imaging revealed that after multiple fission of mother cells, the newly released, lemon-shaped daughter cells began extruding bristles from each pole. In some instances, the bristles became stuck to either the glass floor or polydimethylsiloxane (PDMS) walls of the chamber, and the force by which the new bristle was extruded was sufficient to propel the cells across the field of view at ~1.2 μm · h-1 . Confocal fluorescence and DIC imaging of cells stained with pontamine fast scarlet and calcofluor, and treated with proteinase K, suggested that bristles are proteinaceous and may also host carbohydrate modifications. The polar bristles extruded by this desert-derived T. deserticola may simply be relics of bristles produced by an aquatic ancestor for flotation or predator deterrence. But, their tendency to attach to glass (silicate) and/or PDMS surfaces suggests a potential role in tethering cells in place or binding soil particles. T. deserticola is closely related to T. obliquus, which is of interest for biofuels development; extruded bristles in T. deserticola may offer tethers for industrial use of these stress-tolerant algae.
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Affiliation(s)
- Zoe G Cardon
- Marine Biological Laboratory, Ecosystems Center, Woods Hole, Massachusetts, 02543, USA
| | - Elena L Peredo
- Marine Biological Laboratory, Ecosystems Center, Woods Hole, Massachusetts, 02543, USA
| | - Cassidy M Enloe
- Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - John S Oakey
- Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755, USA
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Chang M, Wu SZ, Ryken SE, O’Sullivan JE, Bezanilla M. COPII Sec23 proteins form isoform-specific endoplasmic reticulum exit sites with differential effects on polarized growth. Plant Cell 2022; 34:333-350. [PMID: 34534343 PMCID: PMC8846183 DOI: 10.1093/plcell/koab229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 05/04/2023]
Abstract
Coat Protein complex II (COPII), a coat protein complex that forms vesicles on the endoplasmic reticulum (ER), mediates trafficking to the Golgi. While metazoans have few genes encoding each COPII component, plants have expanded these gene families, leading to the hypothesis that plant COPII has functionally diversified. In the moss Physcomitrium (Physcomitrella) patens, the Sec23/24 gene families are each composed of seven genes. Silencing Sec23/24 revealed isoform-specific contributions to polarized growth, with the closely related Sec23D/E and Sec24C/D essential for protonemal development. Focusing on Sec23, we discovered that Sec23D/E mediate ER-to Golgi transport and are essential for tip growth, with Sec23D localizing to presumptive ER exit sites. In contrast, Sec23A, B, C, F, and G are dispensable and do not quantitatively affect ER-to-Golgi trafficking. However, Δsec23abcfg plants exhibited reduced secretion of plasma membrane cargo. Of the four highly expressed protonemal Sec23 genes, Sec23F/G are members of a divergent Sec23 clade specifically retained in land plants. Notably, Sec23G accumulates on ER-associated foci that are significantly larger, do not overlap with, and are independent of Sec23D. While Sec23D/E form ER exit sites and function as bona fide COPII components essential for tip-growing protonemata, Sec23G and the closely related Sec23F have likely functionally diversified, forming separate and independent ER exit sites and participating in Golgi-independent trafficking pathways.
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Affiliation(s)
- Mingqin Chang
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
- Plant Biology Graduate Program, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
| | - Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Samantha E Ryken
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Jacquelyn E O’Sullivan
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
- Author for correspondence:
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7
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Kang BH, Anderson CT, Arimura SI, Bayer E, Bezanilla M, Botella MA, Brandizzi F, Burch-Smith TM, Chapman KD, Dünser K, Gu Y, Jaillais Y, Kirchhoff H, Otegui MS, Rosado A, Tang Y, Kleine-Vehn J, Wang P, Zolman BK. A glossary of plant cell structures: Current insights and future questions. Plant Cell 2022; 34:10-52. [PMID: 34633455 PMCID: PMC8846186 DOI: 10.1093/plcell/koab247] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/29/2021] [Indexed: 05/03/2023]
Abstract
In this glossary of plant cell structures, we asked experts to summarize a present-day view of plant organelles and structures, including a discussion of outstanding questions. In the following short reviews, the authors discuss the complexities of the plant cell endomembrane system, exciting connections between organelles, novel insights into peroxisome structure and function, dynamics of mitochondria, and the mysteries that need to be unlocked from the plant cell wall. These discussions are focused through a lens of new microscopy techniques. Advanced imaging has uncovered unexpected shapes, dynamics, and intricate membrane formations. With a continued focus in the next decade, these imaging modalities coupled with functional studies are sure to begin to unravel mysteries of the plant cell.
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Affiliation(s)
- Byung-Ho Kang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Charles T Anderson
- Department of Biology and Center for Lignocellulose Structure and Formation, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | - Shin-ichi Arimura
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Emmanuelle Bayer
- Université de Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, Villenave d'Ornon F-33140, France
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Miguel A Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortifruticultura Subtropical y Mediterránea “La Mayora,” Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga 29071, Spain
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, Michigan 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan 48824, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Kent D Chapman
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203, USA
| | - Kai Dünser
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Yangnan Gu
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Yvon Jaillais
- Laboratoire Reproduction et Développement des Plantes (RDP), Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Lyon, France
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Wisconsin 53706, USA
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver V6T1Z4, Canada
| | - Yu Tang
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Jürgen Kleine-Vehn
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Bethany Karlin Zolman
- Department of Biology, University of Missouri, St. Louis, St. Louis, Missouri 63121, USA
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8
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Weijers D, Bezanilla M, Jiang L, Roeder AHK, Williams M. Back to the roots: A focus on plant cell biology. Plant Cell 2022; 34:1-3. [PMID: 34755878 PMCID: PMC8774064 DOI: 10.1093/plcell/koab278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Affiliation(s)
| | - Magdalena Bezanilla
- Reviewing Editor, The Plant Cell and Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Liwen Jiang
- Guest Editor, The Plant Cell and School of Life Sciences, Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Adrienne H K Roeder
- Guest Editor, The Plant Cell and Weil Institute for Cell and Molecular Biology and School of Integrative Plant Sciences, Section of Plant Biology, Cornell University, Ithaca, NY, USA
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9
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Lara-Rojas F, Juárez-Verdayes M, Wu HM, Cheung AY, Montiel J, Pascual-Morales E, Ryken SE, Bezanilla M, Cardenas L. Using Hyper as a molecular probe to visualize hydrogen peroxide in living plant cells: An updated method. Methods Enzymol 2022; 683:265-289. [PMID: 37087192 DOI: 10.1016/bs.mie.2022.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Reactive oxygen species (ROS) are highly reactive reduced oxygen molecules that play a myriad of roles in animal and plant cells. In plant cells the production of ROS results from aerobic metabolism during respiration and photosynthesis. Therefore mitochondria, chloroplasts, and peroxisomes constitute an important source of ROS. However, ROS can also be produced in response to many physiological stimuli such as pathogen attack, hormone signaling, abiotic stresses or during cell wall organization and plant morphogenesis. The study of ROS in plant cells has been limited to biochemical assays and use of fluorescent probes, however, the irreversible oxidation of the fluorescent dyes prevents the visualization of dynamic changes. We have previously reported that Hyper 1 is a biosensor for H2O2 and consists of a circularly permutated YFP (cpYFP) inserted into the regulatory domain of the Escherichia coli hydrogen peroxide (H2O2) sensor protein OxyR rendering it an H2O2-specific quantitative probe (Bilan & Belousov, 2018; Hernandez-Barrera et al., 2015). Herein we describe an updated protocol for using the improved new version of Hyper 2 and Hyper 3 as a dynamic biosensor for H2O2 in Arabidopsis with virtually unlimited potential to detect H2O2 throughout the plant and under a broad range of developmental and environmental conditions (Bilan et al., 2013).
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10
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Lara-Rojas F, Sarmiento-López LG, Pascual-Morales E, Ryken SE, Bezanilla M, Cardenas L. Using DCP-Rho1 as a fluorescent probe to visualize sulfenic acid-containing proteins in living plant cells. Methods Enzymol 2022; 683:291-308. [PMID: 37087193 DOI: 10.1016/bs.mie.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Among the biologically relevant reactive oxygen species (ROS), hydrogen peroxide (H2O2) has special properties. H2O2 can diffuse across membranes, has a low reactivity, and is very stable. Deprotonated cysteine residues in proteins can be oxidized by H2O2 into a highly reactive sulfenic acid derivative (-SOH), which can react with another cysteine to form a disulfide. Under higher oxidative stress the sulfenic acid undergo further oxidation to sulfinic acid (Cys-SO2H), which can subsequently be reduced. The sulfinic acid can be hyperoxidized to sulfonic acid (Cys-SO3H), whose reduction is irreversible. Formation of sulfenic acids can have a role in sensing oxidative stress, signal transduction, modulating localization and activity to regulate protein functions. Therefore, there is an emerging interest in trying to understand the pool of proteins that result in these sorts of modification in response to oxidative stress. This is known as the sulfenome and several approaches have been developed in animal and plant cells to analyze the sulfenome under different stress responses. These approaches can be proteomic, molecular, immunological (i.e., antibodies), or expressing genetically encoded probes that specifically react to sulfenic modifications. In this chapter, we describe an additional approach that allows visualization of sulfenic modification in vivo. This is newly developed fluorescent probe DCP-Rho1 can be implemented in any plant cell to analyze the sulfenic modification.
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Affiliation(s)
- Fernando Lara-Rojas
- Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Yautepec, Morelos, México
| | | | - Edgar Pascual-Morales
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Samantha E Ryken
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Luis Cardenas
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
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11
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Radin I, Richardson RA, Coomey JH, Weiner ER, Bascom CS, Li T, Bezanilla M, Haswell ES. Plant PIEZO homologs modulate vacuole morphology during tip growth. Science 2021; 373:586-590. [PMID: 34326243 DOI: 10.1126/science.abe6310] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/24/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
In animals, PIEZOs are plasma membrane-localized cation channels involved in diverse mechanosensory processes. We investigated PIEZO function in tip-growing cells in the moss Physcomitrium patens and the flowering plant Arabidopsis thaliana PpPIEZO1 and PpPIEZO2 redundantly contribute to the normal growth, size, and cytoplasmic calcium oscillations of caulonemal cells. Both PpPIEZO1 and PpPIEZO2 localized to vacuolar membranes. Loss-of-function, gain-of-function, and overexpression mutants revealed that moss PIEZO homologs promote increased complexity of vacuolar membranes through tubulation, internalization, and/or fission. Arabidopsis PIEZO1 also localized to the tonoplast and is required for vacuole tubulation in the tips of pollen tubes. We propose that in plant cells the tonoplast has more freedom of movement than the plasma membrane, making it a more effective location for mechanosensory proteins.
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Affiliation(s)
- Ivan Radin
- Department of Biology and NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Ryan A Richardson
- Department of Biology and NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Joshua H Coomey
- Department of Biology and NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Ethan R Weiner
- Department of Biology and NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | | | - Ting Li
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | | | - Elizabeth S Haswell
- Department of Biology and NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA.
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12
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Cheng X, Bezanilla M. SABRE populates ER domains essential for cell plate maturation and cell expansion influencing cell and tissue patterning. eLife 2021; 10:65166. [PMID: 33687329 PMCID: PMC7987345 DOI: 10.7554/elife.65166] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/04/2021] [Indexed: 12/12/2022] Open
Abstract
SABRE, which is found throughout eukaryotes and was originally identified in plants, mediates cell expansion, division plane orientation, and planar polarity in plants. How and where SABRE mediates these processes remain open questions. We deleted SABRE in Physcomitrium patens, an excellent model for cell biology. SABRE null mutants were stunted, similar to phenotypes in seed plants. Additionally, polarized growing cells were delayed in cytokinesis, sometimes resulting in catastrophic failures. A functional SABRE fluorescent fusion protein localized to dynamic puncta on regions of the endoplasmic reticulum (ER) during interphase and at the cell plate during cell division. Without SABRE, cells accumulated ER aggregates and the ER abnormally buckled along the developing cell plate. Notably, callose deposition was delayed in ∆sabre, and in cells that failed to divide, abnormal callose accumulations formed at the cell plate. Our findings revealed a surprising and fundamental role for the ER in cell plate maturation.
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Affiliation(s)
- Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, United States
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, United States
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13
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Cheng X, Mwaura BW, Chang Stauffer SR, Bezanilla M. A Fully Functional ROP Fluorescent Fusion Protein Reveals Roles for This GTPase in Subcellular and Tissue-Level Patterning. Plant Cell 2020; 32:3436-3451. [PMID: 32917738 PMCID: PMC7610296 DOI: 10.1105/tpc.20.00440] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/25/2020] [Accepted: 09/07/2020] [Indexed: 05/18/2023]
Abstract
Rho of Plants (ROPs) are GTPases that regulate polarity and patterned wall deposition in plants. As these small, globular proteins have many interactors, it has been difficult to ensure that methods to visualize ROP in live cells do not affect ROP function. Here, motivated by work in fission yeast (Schizosaccharomyces pombe), we generated a fluorescent moss (Physcomitrium [Physcomitrella] patens) ROP4 fusion protein by inserting mNeonGreen after Gly-134. Plants harboring tagged ROP4 and no other ROP genes were phenotypically normal. Plants lacking all four ROP genes comprised an unpatterned clump of spherical cells that were unable to form gametophores, demonstrating that ROP is essentially for spatial patterning at the cellular and tissue levels. The functional ROP fusion protein formed a steep gradient at the apical plasma membranes of growing tip cells. ROP also predicted the site of branch formation in the apical cell at the onset of mitosis, which occurs one to two cell cycles before a branch cell emerges. While fluorescence recovery after photobleaching studies demonstrated that ROP dynamics do not depend on the cytoskeleton, acute depolymerization of the cytoskeleton removed ROP from the membrane only in recently divided cells, pointing to a feedback mechanism between the cell cycle, cytoskeleton, and ROP.
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Affiliation(s)
- Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | - Bethany W Mwaura
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | | | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
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14
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Rensing SA, Goffinet B, Meyberg R, Wu SZ, Bezanilla M. The Moss Physcomitrium ( Physcomitrella) patens: A Model Organism for Non-Seed Plants. Plant Cell 2020; 32:1361-1376. [PMID: 32152187 PMCID: PMC7203925 DOI: 10.1105/tpc.19.00828] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/17/2020] [Accepted: 03/05/2020] [Indexed: 05/06/2023]
Abstract
Since the discovery two decades ago that transgenes are efficiently integrated into the genome of Physcomitrella patens by homologous recombination, this moss has been a premier model system to study evolutionary developmental biology questions, stem cell reprogramming, and the biology of nonvascular plants. P patens was the first non-seed plant to have its genome sequenced. With this level of genomic information, together with increasing molecular genetic tools, a large number of reverse genetic studies have propelled the use of this model system. A number of technological advances have recently opened the door to forward genetics as well as extremely efficient and precise genome editing in P patens Additionally, careful phylogenetic studies with increased resolution have suggested that P patens emerged from within Physcomitrium Thus, rather than Physcomitrella patens, the species should be named Physcomitrium patens Here we review these advances and describe the areas where P patens has had the most impact on plant biology.
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Affiliation(s)
- Stefan A Rensing
- Faculty of Biology, Plant Cell Biology, Philipps University of Marburg, 35037 Marburg an der Lahn, Hesse, Germany
| | - Bernard Goffinet
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269
| | - Rabea Meyberg
- Faculty of Biology, Plant Cell Biology, Philipps University of Marburg, 35037 Marburg an der Lahn, Hesse, Germany
| | - Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
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15
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Tang H, Duijts K, Bezanilla M, Scheres B, Vermeer JEM, Willemsen V. Geometric cues forecast the switch from two- to three-dimensional growth in Physcomitrella patens. New Phytol 2020; 225:1945-1955. [PMID: 31639220 PMCID: PMC7027797 DOI: 10.1111/nph.16276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/12/2019] [Indexed: 05/02/2023]
Abstract
During land colonization, plants acquired a range of body plan adaptations, of which the innovation of three-dimensional (3D) tissues increased organismal complexity and reproductivity. In the moss, Physcomitrella patens, a 3D leafy gametophore originates from filamentous cells that grow in a two-dimensional (2D) plane through a series of asymmetric cell divisions. Asymmetric cell divisions that coincide with different cell division planes and growth directions enable the developmental switch from 2D to 3D, but insights into the underlying mechanisms coordinating this switch are still incomplete. Using 2D and 3D imaging and image segmentation, we characterized two geometric cues, the width of the initial cell and the angle of the transition division plane, which sufficiently distinguished a gametophore initial cell from a branch initial cell. These identified cues were further confirmed in gametophore formation mutants. The identification of a fluorescent marker allowed us to successfully predict the gametophore initial cell with > 90% accuracy before morphological changes, supporting our hypothesis that, before the transition division, parental cells of the gametophore initials possess different properties from those of the branch initials. Our results suggest that the cell fate decision of the initial cell is determined in the parental cell, before the transition division.
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Affiliation(s)
- Han Tang
- Laboratory of Plant Developmental BiologyWageningen University & Research6708 PBWageningenthe Netherlands
- Laboratory of Cell BiologyWageningen University & Research6708 PEWageningenthe Netherlands
| | - Kilian Duijts
- Laboratory of Cell BiologyWageningen University & Research6708 PEWageningenthe Netherlands
| | | | - Ben Scheres
- Laboratory of Plant Developmental BiologyWageningen University & Research6708 PBWageningenthe Netherlands
| | - Joop E. M. Vermeer
- Laboratory of Cell and Molecular BiologyInstitute of BiologyUniversity of Neuchâtel2000NeuchâtelSwitzerland
| | - Viola Willemsen
- Laboratory of Plant Developmental BiologyWageningen University & Research6708 PBWageningenthe Netherlands
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16
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van Gisbergen P, Wu SZ, Cheng X, Pattavina KA, Bezanilla M. In vivo analysis of formin dynamics in the moss P. patens reveals functional class diversification. J Cell Sci 2020; 133:jcs233791. [PMID: 31969472 PMCID: PMC10679510 DOI: 10.1242/jcs.233791] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 01/07/2020] [Indexed: 01/02/2023] Open
Abstract
Formins are actin regulators critical for diverse processes across eukaryotes. With many formins in plants and animals, it has been challenging to determine formin function in vivo We found that the phylogenetically distinct class I integral membrane formins (denoted For1) from the moss P.patens enrich at sites of membrane turnover, with For1D more tightly associated with the plasma membrane than For1A. To probe formin function, we generated formin-null lines with greatly reduced formin complexity. We found that For1A and For1D help to anchor actin near the cell apex, with For1A contributing to formation of cytosolic actin, while For1D contributes to plasma membrane-associated actin. At the cortex, For1A and For1D localized to motile puncta and differentially impacted actin dynamics. We found that class I cortical formin mobility depended on microtubules and only moderately on actin, whereas class II formin (denoted For2) mobility solely depended on actin. Moreover, cortical For2A tightly correlated with the puncta labeled by the endocytic membrane dye FM4-64, and null mutants in class I formins did not affect uptake of a similar dye, FM1-43, suggesting that class I and II formins are involved in distinct membrane trafficking pathways.
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Affiliation(s)
- Peter van Gisbergen
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Kelli A Pattavina
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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17
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Orr RG, Cheng X, Vidali L, Bezanilla M. Orchestrating cell morphology from the inside out - using polarized cell expansion in plants as a model. Curr Opin Cell Biol 2019; 62:46-53. [PMID: 31546159 DOI: 10.1016/j.ceb.2019.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 12/16/2022]
Abstract
Intracellular organization forms the basis of changes in the extracellular matrix. In walled cells, these changes are essential for morphogenesis and growth. The highly polarized cells of mosses and liverworts together with root hairs and pollen tubes are geometrically simple cells that develop in the absence of complex tissue-scale signaling, providing an excellent model to study cell polarity. Recent advances present a unifying theme where the cytoskeleton and its associated motors work in coordination with vesicle trafficking. This coordination results in a recycling system near the cell tip, where endocytosed molecules are sorted and combined with exocytic cargo driving growth. Interestingly, functional similarities between filamentous fungi and plants promise to advance our understanding of cell polarization and growth across kingdoms.
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Affiliation(s)
- Robert G Orr
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester MA, 01609, United States
| | - Xiaohang Cheng
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, United States
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester MA, 01609, United States
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, United States.
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18
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Mallett DR, Chang M, Cheng X, Bezanilla M. Efficient and modular CRISPR-Cas9 vector system for Physcomitrella patens. Plant Direct 2019; 3:e00168. [PMID: 31523744 PMCID: PMC6739617 DOI: 10.1002/pld3.168] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/29/2019] [Accepted: 08/20/2019] [Indexed: 05/20/2023]
Abstract
CRISPR-Cas9 has been shown to be a valuable tool in recent years, allowing researchers to precisely edit the genome using an RNA-guided nuclease to initiate double-strand breaks. Until recently, classical RAD51-mediated homologous recombination has been a powerful tool for gene targeting in the moss Physcomitrella patens. However, CRISPR-Cas9-mediated genome editing in P. patens was shown to be more efficient than traditional homologous recombination (Plant Biotechnology Journal, 15, 2017, 122). CRISPR-Cas9 provides the opportunity to efficiently edit the genome at multiple loci as well as integrate sequences at precise locations in the genome using a simple transient transformation. To fully take advantage of CRISPR-Cas9 genome editing in P. patens, here we describe the generation and use of a flexible and modular CRISPR-Cas9 vector system. Without the need for gene synthesis, this vector system enables editing of up to 12 loci simultaneously. Using this system, we generated multiple lines that had null alleles at four distant loci. We also found that targeting multiple sites within a single locus can produce larger deletions, but the success of this depends on individual protospacers. To take advantage of homology-directed repair, we developed modular vectors to rapidly generate DNA donor plasmids to efficiently introduce DNA sequences encoding for fluorescent proteins at the 5' and 3' ends of gene coding regions. With regard to homology-directed repair experiments, we found that if the protospacer sequence remains on the DNA donor plasmid, then Cas9 cleaves the plasmid target as well as the genomic target. This can reduce the efficiency of introducing sequences into the genome. Furthermore, to ensure the generation of a null allele near the Cas9 cleavage site, we generated a homology plasmid harboring a "stop codon cassette" with downstream near-effortless genotyping.
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Affiliation(s)
- Darren R. Mallett
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
| | - Mingqin Chang
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
- Plant Biology Graduate ProgramUniversity of MassachusettsAmherstMassachusetts
| | - Xiaohang Cheng
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
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19
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Bezanilla M, Wu SZ, Bascom C, Yamada M, Chang X. Cytoskeletal Dynamics during Polarized Growth. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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20
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Bascom C, Burkart GM, Mallett DR, O’Sullivan JE, Tomaszewski AJ, Walsh K, Bezanilla M. Systematic survey of the function of ROP regulators and effectors during tip growth in the moss Physcomitrella patens. J Exp Bot 2019; 70:447-457. [PMID: 30380098 PMCID: PMC6322563 DOI: 10.1093/jxb/ery376] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/18/2018] [Indexed: 05/03/2023]
Abstract
Rho/Rac of plants (ROP) GTPases are plant-specific small GTPases that regulate cell morphology. ROP activity is controlled by several families of regulatory proteins. However, how these diverse regulators contribute to polarized growth remains understudied. In a system-wide approach, we used RNAi to silence each gene family of known ROP regulators in the juvenile tissues of the moss Physcomitrella patens. We found that the GTPase activating proteins, but not the ROP enhancers, are essential for tip growth. The guanine exchange factors (GEFs), which are comprised of ROPGEFs and Spikes, both contribute to growth. However, silencing Spikes results in less-polarized plants as compared to silencing ROPGEFs, suggesting that Spikes contribute more to establishing cell polarity. Silencing the single-gene family of guanine dissociation inhibitors also inhibits growth, resulting in small, unpolarized plants. In contrast, silencing the ROP effector ROP-interactive CRIB-containing (RIC) protein, which is encoded by a single gene, results in plants larger than the controls, suggesting that RIC functions to inhibit tip growth in moss. Taken together, this systematic loss-of-function survey provides insights into the function of ROP regulators during polarized growth.
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Affiliation(s)
- Carlisle Bascom
- Plant Biology Graduate Program, University of Massachusetts, Amherst, USA
- Department of Biological Sciences, Dartmouth College, Hanover NH, USA
| | - Graham M Burkart
- Plant Biology Graduate Program, University of Massachusetts, Amherst, USA
| | - Darren R Mallett
- Department of Biological Sciences, Dartmouth College, Hanover NH, USA
- Biology Department, University of Massachusetts, Amherst, USA
| | | | | | - Katherine Walsh
- Biology Department, University of Massachusetts, Amherst, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover NH, USA
- Correspondence:
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21
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Wu SZ, Yamada M, Mallett DR, Bezanilla M. Cytoskeletal discoveries in the plant lineage using the moss Physcomitrella patens. Biophys Rev 2018; 10:1683-1693. [PMID: 30382556 DOI: 10.1007/s12551-018-0470-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/21/2018] [Indexed: 12/16/2022] Open
Abstract
Advances in cell biology have been largely driven by pioneering work in model systems, the majority of which are from one major eukaryotic lineage, the opisthokonts. However, with the explosion of genomic information in many lineages, it has become clear that eukaryotes have incredible diversity in many cellular systems, including the cytoskeleton. By identifying model systems in diverse lineages, it may be possible to begin to understand the evolutionary origins of the eukaryotic cytoskeleton. Within the plant lineage, cell biological studies in the model moss, Physcomitrella patens, have over the past decade provided key insights into how the cytoskeleton drives cell and tissue morphology. Here, we review P. patens attributes that make it such a rich resource for cytoskeletal cell biological inquiry and highlight recent key findings with regard to intracellular transport, microtubule-actin interactions, and gene discovery that promises for many years to provide new cytoskeletal players.
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Affiliation(s)
- Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, 03755, USA
| | - Moe Yamada
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, 03755, USA
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Darren R Mallett
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, 03755, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH, 03755, USA.
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22
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Handakumbura PP, Brow K, Whitney IP, Zhao K, Sanguinet KA, Lee SJ, Olins J, Romero-Gamboa SP, Harrington MJ, Bascom CJ, MacKinnon KJM, Veling MT, Liu L, Lee JE, Vogel JP, O'Malley RC, Bezanilla M, Bartley LE, Hazen SP. SECONDARY WALL ASSOCIATED MYB1 is a positive regulator of secondary cell wall thickening in Brachypodium distachyon and is not found in the Brassicaceae. Plant J 2018; 96:532-545. [PMID: 30054951 DOI: 10.1111/tpj.14047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/14/2018] [Accepted: 07/18/2018] [Indexed: 05/11/2023]
Abstract
Grass biomass is comprised chiefly of secondary walls that surround fiber and xylem cells. A regulatory network of interacting transcription factors in part regulates cell wall thickening. We identified Brachypodium distachyon SECONDARY WALL ASSOCIATED MYB1 (SWAM1) as a potential regulator of secondary cell wall biosynthesis based on gene expression, phylogeny, and transgenic plant phenotypes. SWAM1 interacts with cellulose and lignin gene promoters with preferential binding to AC-rich sequence motifs commonly found in the promoters of cell wall-related genes. SWAM1 overexpression (SWAM-OE) lines had greater above-ground biomass with only a slight change in flowering time while SWAM1 dominant repressor (SWAM1-DR) plants were severely dwarfed with a striking reduction in lignin of sclerenchyma fibers and stem epidermal cell length. Cellulose, hemicellulose, and lignin genes were significantly down-regulated in SWAM1-DR plants and up-regulated in SWAM1-OE plants. There was no reduction in bioconversion yield in SWAM1-OE lines; however, it was significantly increased for SWAM1-DR samples. Phylogenetic and syntenic analyses strongly suggest that the SWAM1 clade was present in the last common ancestor between eudicots and grasses, but is not in the Brassicaceae. Collectively, these data suggest that SWAM1 is a transcriptional activator of secondary cell wall thickening and biomass accumulation in B. distachyon.
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Affiliation(s)
- Pubudu P Handakumbura
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kathryn Brow
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Ian P Whitney
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kangmei Zhao
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Karen A Sanguinet
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164, USA
| | - Scott J Lee
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Jennifer Olins
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Sandra P Romero-Gamboa
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Carlisle J Bascom
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kirk J-M MacKinnon
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Michael T Veling
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Lifeng Liu
- DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Ji E Lee
- DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - John P Vogel
- DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | | | | | - Laura E Bartley
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Samuel P Hazen
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
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23
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Wu SZ, Bezanilla M. Actin and microtubule cross talk mediates persistent polarized growth. J Cell Biol 2018; 217:3531-3544. [PMID: 30061106 PMCID: PMC6168251 DOI: 10.1083/jcb.201802039] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/08/2018] [Accepted: 07/10/2018] [Indexed: 11/25/2022] Open
Abstract
How the actin and microtubule cytoskeletons work together during diverse cellular functions is unclear. Wu et al. describe an apical actin pool in plant cells organized by a microtubule template at the site of polarized growth. Disconnecting the two cytoskeletons by removing class VIII myosins alters both cytoskeletal structures and impairs polarized growth. Coordination between actin and microtubules is important for numerous cellular processes in diverse eukaryotes. In plants, tip-growing cells require actin for cell expansion and microtubules for orientation of cell expansion, but how the two cytoskeletons are linked is an open question. In tip-growing cells of the moss Physcomitrella patens, we show that an actin cluster near the cell apex dictates the direction of rapid cell expansion. Formation of this structure depends on the convergence of microtubules near the cell tip. We discovered that microtubule convergence requires class VIII myosin function, and actin is necessary for myosin VIII–mediated focusing of microtubules. The loss of myosin VIII function affects both networks, indicating functional connections among the three cytoskeletal components. Our data suggest that microtubules direct localization of formins, actin nucleation factors, that generate actin filaments further focusing microtubules, thereby establishing a positive feedback loop ensuring that actin polymerization and cell expansion occur at a defined site resulting in persistent polarized growth.
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Affiliation(s)
- Shu-Zon Wu
- Department of Biological Sciences, Dartmouth College, Hanover, NH
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24
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Ding X, Pervere LM, Bascom C, Bibeau JP, Khurana S, Butt AM, Orr RG, Flaherty PJ, Bezanilla M, Vidali L. Conditional genetic screen in Physcomitrella patens reveals a novel microtubule depolymerizing-end-tracking protein. PLoS Genet 2018; 14:e1007221. [PMID: 29746462 PMCID: PMC5944918 DOI: 10.1371/journal.pgen.1007221] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/24/2018] [Indexed: 11/19/2022] Open
Abstract
Our ability to identify genes that participate in cell growth and division is limited because their loss often leads to lethality. A solution to this is to isolate conditional mutants where the phenotype is visible under restrictive conditions. Here, we capitalize on the haploid growth-phase of the moss Physcomitrella patens to identify conditional loss-of-growth (CLoG) mutants with impaired growth at high temperature. We used whole-genome sequencing of pooled segregants to pinpoint the lesion of one of these mutants (clog1) and validated the identified mutation by rescuing the conditional phenotype by homologous recombination. We found that CLoG1 is a novel and ancient gene conserved in plants. At the restrictive temperature, clog1 plants have smaller cells but can complete cell division, indicating an important role of CLoG1 in cell growth, but not an essential role in cell division. Fluorescent protein fusions of CLoG1 indicate it is localized to microtubules with a bias towards depolymerizing microtubule ends. Silencing CLoG1 decreases microtubule dynamics, suggesting that CLoG1 plays a critical role in regulating microtubule dynamics. By discovering a novel gene critical for plant growth, our work demonstrates that P. patens is an excellent genetic system to study genes with a fundamental role in plant cell growth.
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Affiliation(s)
- Xinxin Ding
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA
| | - Leah M. Pervere
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA
| | - Carl Bascom
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA
- Department of Biological Sciences, Dartmouth College, Hanover, NH
| | - Jeffrey P. Bibeau
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
| | - Sakshi Khurana
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
| | - Allison M. Butt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
| | - Robert G. Orr
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
| | - Patrick J. Flaherty
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA
- Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA
| | | | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA
- * E-mail:
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25
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Cardon ZG, Peredo EL, Dohnalkova AC, Gershone HL, Bezanilla M. A model suite of green algae within the Scenedesmaceae for investigating contrasting desiccation tolerance and morphology. J Cell Sci 2018; 131:jcs.212233. [PMID: 29487180 DOI: 10.1242/jcs.212233] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/15/2018] [Indexed: 12/13/2022] Open
Abstract
Microscopic green algae inhabiting desert microbiotic crusts are remarkably diverse phylogenetically, and many desert lineages have independently evolved from aquatic ancestors. Here we worked with five desert and aquatic species within the family Scenedesmaceae to examine mechanisms that underlie desiccation tolerance and release of unicellular versus multicellular progeny. Live cell staining and time-lapse confocal imaging coupled with transmission electron microscopy established that the desert and aquatic species all divide by multiple (rather than binary) fission, although progeny were unicellular in three species and multicellular (joined in a sheet-like coenobium) in two. During division, Golgi complexes were localized near nuclei, and all species exhibited dynamic rotation of the daughter cell mass within the mother cell wall at cytokinesis. Differential desiccation tolerance across the five species, assessed from photosynthetic efficiency during desiccation/rehydration cycles, was accompanied by differential accumulation of intracellular reactive oxygen species (ROS) detected using a dye sensitive to intracellular ROS. Further comparative investigation will aim to understand the genetic, ultrastructural and physiological characteristics supporting unicellular versus multicellular coenobial morphology, and the ability of representatives in the Scenedesmaceae to colonize ecologically diverse, even extreme, habitats.
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Affiliation(s)
- Zoe G Cardon
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Elena L Peredo
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Alice C Dohnalkova
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Hannah L Gershone
- Biological Sciences and Environmental Studies Departments, Mt. Holyoke College, South Hadley, MA 01075 USA
| | - Magdalena Bezanilla
- Department of Biology, University of Massachusetts, Amherst, MA 01003 USA.,Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
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26
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van Gisbergen PAC, Wu SZ, Chang M, Pattavina KA, Bartlett ME, Bezanilla M. An ancient Sec10-formin fusion provides insights into actin-mediated regulation of exocytosis. J Cell Biol 2018; 217:945-957. [PMID: 29374070 PMCID: PMC5839782 DOI: 10.1083/jcb.201705084] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 12/21/2017] [Accepted: 01/08/2018] [Indexed: 11/22/2022] Open
Abstract
Interactions between actin nucleators and the exocyst in yeast and mammals control membrane remodeling. van Gisbergen et al. now describe For1F, a fusion of an exocyst subunit (Sec10) and an actin nucleation factor (formin), retained in the moss lineage for more than 170 million years, which provides unique insight into the regulation of exocytosis by actin. Exocytosis, facilitated by the exocyst, is fundamentally important for remodeling cell walls and membranes. Here, we analyzed For1F, a novel gene that encodes a fusion of an exocyst subunit (Sec10) and an actin nucleation factor (formin). We showed that the fusion occurred early in moss evolution and has been retained for more than 170 million years. In Physcomitrella patens, For1F is essential, and the expressed protein is a fusion of Sec10 and formin. Reduction of For1F or actin filaments inhibits exocytosis, and For1F dynamically associates with Sec6, another exocyst subunit, in an actin-dependent manner. Complementation experiments demonstrate that constitutive expression of either half of the gene or the paralogous Sec10b rescues loss of For1F, suggesting that fusion of the two domains is not essential, consistent with findings in yeast, where formin and the exocyst are linked noncovalently. Although not essential, the fusion may have had selective advantages and provides a unique opportunity to probe actin regulation of exocytosis.
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Affiliation(s)
| | - Shu-Zon Wu
- Biological Sciences Department, Dartmouth College, Hanover, NH
| | - Mingqin Chang
- Biological Sciences Department, Dartmouth College, Hanover, NH.,Plant Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA
| | - Kelli A Pattavina
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA
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27
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Bascom CS, Hepler PK, Bezanilla M. Interplay between Ions, the Cytoskeleton, and Cell Wall Properties during Tip Growth. Plant Physiol 2018; 176:28-40. [PMID: 29138353 PMCID: PMC5761822 DOI: 10.1104/pp.17.01466] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/05/2017] [Indexed: 05/08/2023]
Abstract
Tip growth is a focused and tightly regulated apical explosion that depends on the interconnected activities of ions, the cytoskeleton, and the cell wall.
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Affiliation(s)
- Carlisle S Bascom
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
- Plant Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts 01002
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01002
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
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28
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Russell JJ, Theriot JA, Sood P, Marshall WF, Landweber LF, Fritz-Laylin L, Polka JK, Oliferenko S, Gerbich T, Gladfelter A, Umen J, Bezanilla M, Lancaster MA, He S, Gibson MC, Goldstein B, Tanaka EM, Hu CK, Brunet A. Non-model model organisms. BMC Biol 2017; 15:55. [PMID: 28662661 PMCID: PMC5492503 DOI: 10.1186/s12915-017-0391-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Model organisms are widely used in research as accessible and convenient systems to study a particular area or question in biology. Traditionally only a handful of organisms have been widely studied, but modern research tools are enabling researchers to extend the set of model organisms to include less-studied and more unusual systems. This Forum highlights a range of 'non-model model organisms' as emerging systems for tackling questions across the whole spectrum of biology (and beyond), the opportunities and challenges, and the outlook for the future.
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Affiliation(s)
- James J Russell
- Department of Biology, Howard Hughes Medical Institute Stanford University, Stanford, CA, 94305, USA
| | - Julie A Theriot
- Departments of Biochemistry and of Microbiology & Immunology, Howard Hughes Medical Institute Stanford University, Stanford, CA, 94305, USA.
| | - Pranidhi Sood
- Department of Biochemistry & Biophysics, University of California San Francisco, 600 16th St, San Francisco, CA, 94158, USA
| | - Wallace F Marshall
- Department of Biochemistry & Biophysics, University of California San Francisco, 600 16th St, San Francisco, CA, 94158, USA.
| | - Laura F Landweber
- Departments of Biochemistry & Molecular Biophysics and Biological Sciences, Columbia University, New York, NY, 10032, USA
| | | | - Jessica K Polka
- Visiting Scholar, Whitehead Institute, 9 Cambridge Center, Cambridge, MA, 02142, USA
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.,Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London, SE1 1UL, UK
| | - Therese Gerbich
- 516 Fordham Hall, University of North Carolina Chapel Hill, Chapel Hill, NC, 27514, USA
| | - Amy Gladfelter
- 516 Fordham Hall, University of North Carolina Chapel Hill, Chapel Hill, NC, 27514, USA
| | - James Umen
- Donald Danforth Plant Science Center, 975 N. Warson Rd, St. Louis, MO, 63132, USA
| | | | - Madeline A Lancaster
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, CB2 0QH, Cambridge, UK
| | - Shuonan He
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Matthew C Gibson
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA.,Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, KS, 66160, USA
| | - Bob Goldstein
- Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Elly M Tanaka
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - Chi-Kuo Hu
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA.,Glenn Laboratories for the Biology of Aging at Stanford, Stanford, CA, 94305, USA
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29
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Bascom CS, Wu SZ, Nelson K, Oakey J, Bezanilla M. Long-Term Growth of Moss in Microfluidic Devices Enables Subcellular Studies in Development. Plant Physiol 2016; 172:28-37. [PMID: 27406170 PMCID: PMC5074637 DOI: 10.1104/pp.16.00879] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/08/2016] [Indexed: 05/20/2023]
Abstract
Key developmental processes that occur on the subcellular and cellular level or occur in occluded tissues are difficult to access, let alone image and analyze. Recently, culturing living samples within polydimethylsiloxane (PDMS) microfluidic devices has facilitated the study of hard-to-reach developmental events. Here, we show that an early diverging land plant, Physcomitrella patens, can be continuously cultured within PDMS microfluidic chambers. Because the PDMS chambers are bonded to a coverslip, it is possible to image P. patens development at high resolution over long time periods. Using PDMS chambers, we report that wild-type protonemal tissue grows at the same rate as previously reported for growth on solid medium. Using long-term imaging, we highlight key developmental events, demonstrate compatibility with high-resolution confocal microscopy, and obtain growth rates for a slow-growing mutant. By coupling the powerful genetic tools available to P. patens with long-term growth and imaging provided by PDMS microfluidic chambers, we demonstrate the capability to study cellular and subcellular developmental events in plants directly and in real time.
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Affiliation(s)
- Carlisle S Bascom
- Department of Biology (C.S.B., S.-Z.W., M.B.) and Plant Biology Graduate Program (C.S.B.), University of Massachusetts, Amherst, Massachusetts 01003; andDepartment of Chemical Engineering (K.N., J.O.) and Department of Molecular Biology (K.N.), University of Wyoming, Laramie, Wyoming 82071
| | - Shu-Zon Wu
- Department of Biology (C.S.B., S.-Z.W., M.B.) and Plant Biology Graduate Program (C.S.B.), University of Massachusetts, Amherst, Massachusetts 01003; andDepartment of Chemical Engineering (K.N., J.O.) and Department of Molecular Biology (K.N.), University of Wyoming, Laramie, Wyoming 82071
| | - Katherine Nelson
- Department of Biology (C.S.B., S.-Z.W., M.B.) and Plant Biology Graduate Program (C.S.B.), University of Massachusetts, Amherst, Massachusetts 01003; andDepartment of Chemical Engineering (K.N., J.O.) and Department of Molecular Biology (K.N.), University of Wyoming, Laramie, Wyoming 82071
| | - John Oakey
- Department of Biology (C.S.B., S.-Z.W., M.B.) and Plant Biology Graduate Program (C.S.B.), University of Massachusetts, Amherst, Massachusetts 01003; andDepartment of Chemical Engineering (K.N., J.O.) and Department of Molecular Biology (K.N.), University of Wyoming, Laramie, Wyoming 82071
| | - Magdalena Bezanilla
- Department of Biology (C.S.B., S.-Z.W., M.B.) and Plant Biology Graduate Program (C.S.B.), University of Massachusetts, Amherst, Massachusetts 01003; andDepartment of Chemical Engineering (K.N., J.O.) and Department of Molecular Biology (K.N.), University of Wyoming, Laramie, Wyoming 82071
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30
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Saavedra L, Catarino R, Heinz T, Heilmann I, Bezanilla M, Malhó R. Phosphatase and Tensin Homolog Is a Growth Repressor of Both Rhizoid and Gametophore Development in the Moss Physcomitrella patens. Plant Physiol 2015; 169:2572-86. [PMID: 26463087 PMCID: PMC4677911 DOI: 10.1104/pp.15.01197] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/08/2015] [Indexed: 05/19/2023]
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a lipid phosphatase implicated in cellular proliferation and survival. In animal cells, loss of PTEN leads to increased levels of phosphatidylinositol (3,4,5)-trisphosphate, stimulation of glucose and lipid metabolism, cellular growth, and morphological changes (related to adaptation and survival). Intriguingly, in plants, phosphatidylinositol (3,4,5)-trisphosphate has not been detected, and the enzymes that synthesize it were never reported. In this study we performed a genetic, biochemical, and functional characterization of the moss Physcomitrella patens PTEN gene family. P. patens has four PTENs, which are ubiquitously expressed during the entire moss life cycle. Using a knock-in approach, we show that all four genes are expressed in growing tissues, namely caulonemal and rhizoid cells. At the subcellular level, PpPTEN-green fluorescent protein fusions localized to the cytosol and the nucleus. Analysis of single and double knockouts revealed no significant phenotypes at different developmental stages, indicative of functional redundancy. However, compared with wild-type triple and quadruple pten knockouts, caulonemal cells grew faster, switched from the juvenile protonemal stage to adult gametophores earlier, and produced more rhizoids. Furthermore, analysis of lipid content and quantitative real-time polymerase chain reaction data performed in quadruple mutants revealed altered phosphoinositide levels [increase in phosphatidylinositol (3,5)-bisphosphate and decrease in phosphatidylinositol 3-phosphate] and up-regulation of marker genes from the synthesis phase of the cell cycle (e.g. P. patens proliferating cell nuclear antigen, ribonucleotide reductase, and minichromosome maintenance) and of the retinoblastoma-related protein gene P. patens retinoblastoma-related protein1. Together, these results suggest that PpPTEN is a suppressor of cell growth and morphogenic development in plants.
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Affiliation(s)
- Laura Saavedra
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
| | - Rita Catarino
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
| | - Tobias Heinz
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
| | - Ingo Heilmann
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
| | - Magdalena Bezanilla
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
| | - Rui Malhó
- Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal (L.S., R.C., R.M.);Institute of Biochemistry and Biotechnology/Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany (T.H., I.H.); andUniversity of Massachusetts, Amherst, Massachusetts 01003 (M.B.)
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31
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Abstract
Many aspects of cytoskeletal assembly and dynamics can be recapitulated in vitro; yet, how the cytoskeleton integrates signals in vivo across cellular membranes is far less understood. Recent work has demonstrated that the membrane alone, or through membrane-associated proteins, can effect dynamic changes to the cytoskeleton, thereby impacting cell physiology. Having identified mechanistic links between membranes and the actin, microtubule, and septin cytoskeletons, these studies highlight the membrane’s central role in coordinating these cytoskeletal systems to carry out essential processes, such as endocytosis, spindle positioning, and cellular compartmentalization.
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Affiliation(s)
- Magdalena Bezanilla
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003
| | - Amy S Gladfelter
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology and Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637 Department of Molecular Genetics and Cell Biology and Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637
| | - Wei-Lih Lee
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003
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32
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Burkart GM, Baskin TI, Bezanilla M. A family of ROP proteins that suppresses actin dynamics, and is essential for polarized growth and cell adhesion. J Cell Sci 2015; 128:2553-64. [PMID: 26045445 DOI: 10.1242/jcs.172445] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/31/2015] [Indexed: 01/22/2023] Open
Abstract
In plants, the ROP family of small GTPases has been implicated in the polarized growth of tip-growing cells, such as root hairs and pollen tubes; however, most of the data derive from overexpressing ROP genes or constitutively active and dominant-negative isoforms, whereas confirmation by using loss-of-function studies has generally been lacking. Here, in the model moss Physcomitrella patens, we study ROP signaling during tip growth by using a loss-of-function approach based on RNA interference (RNAi) to silence the entire moss ROP family. We find that plants with reduced expression of ROP genes, in addition to failing to initiate tip growth, have perturbed cell wall staining, reduced cell adhesion and have increased actin-filament dynamics. Although plants subjected to RNAi against the ROP family also have reduced microtubule dynamics, this reduction is not specific to loss of ROP genes, as it occurs when actin function is compromised chemically or genetically. Our data suggest that ROP proteins polarize the actin cytoskeleton by suppressing actin-filament dynamics, leading to an increase in actin filaments at the site of polarized secretion.
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Affiliation(s)
- Graham M Burkart
- Department of Biology, University of Massachusetts-Amherst, 611 N. Pleasant Street, Amherst, MA 01003, USA Plant Biology Graduate Program, University of Massachusetts-Amherst, 611 N. Pleasant Street, Amherst, MA 01003, USA
| | - Tobias I Baskin
- Department of Biology, University of Massachusetts-Amherst, 611 N. Pleasant Street, Amherst, MA 01003, USA
| | - Magdalena Bezanilla
- Department of Biology, University of Massachusetts-Amherst, 611 N. Pleasant Street, Amherst, MA 01003, USA
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33
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Wu SZ, Bezanilla M. Myosin VIII associates with microtubule ends and together with actin plays a role in guiding plant cell division. eLife 2014; 3. [PMID: 25247701 PMCID: PMC4171706 DOI: 10.7554/elife.03498] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/28/2014] [Indexed: 11/13/2022] Open
Abstract
Plant cells divide using the phragmoplast, a microtubule-based structure that directs vesicles secretion to the nascent cell plate. The phragmoplast forms at the cell center and expands to reach a specified site at the cell periphery, tens or hundreds of microns distant. The mechanism responsible for guiding the phragmoplast remains largely unknown. Here, using both moss and tobacco, we show that myosin VIII associates with the ends of phragmoplast microtubules and together with actin plays a role in guiding phragmoplast expansion to the cortical division site. Our data lead to a model whereby myosin VIII links phragmoplast microtubules to the cortical division site via actin filaments. Myosin VIII's motor activity along actin provides a molecular mechanism for steering phragmoplast expansion. DOI:http://dx.doi.org/10.7554/eLife.03498.001 Plant cells are surrounded by a membrane, which controls what enters and leaves the cell, and a cell wall, which provides rigidity. When a plant cell is ready to divide, it needs to produce two new cell membranes, with a new cell wall sandwiched between them, to split the cell contents into two daughter cells. During the division process the cell builds a scaffold called the phragmoplast that guides the delivery of the materials that are needed to make the new cell wall and membranes. The phragmoplast—which is made of rod-like proteins called microtubules and actin filaments—starts at the centre of the cell and expands towards a pre-determined site on the existing cell wall. The question is: how does the phragmoplast target this site, which can be tens or hundreds of microns away? Wu and Bezanilla have now found that a protein called myosin VIII has a central role in guiding the growing phragmoplast to the cell wall. Myosin VIII is a motor protein that moves along actin filaments. Wu and Bezanilla propose that myosin VIII can guide the expansion of the phragmoplast by pulling microtubules along the actin filaments. The experiments were carried out on two distantly-related plant species, tobacco and a moss called Physcomitrella patens. Similar results were found in both species so it is possible that myosin VIII may play the same role in cell division in all plants. DOI:http://dx.doi.org/10.7554/eLife.03498.002
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Affiliation(s)
- Shu-Zon Wu
- Department of Biology, University of Massachusetts, Amherst, Amherst, United States
| | - Magdalena Bezanilla
- Department of Biology, University of Massachusetts, Amherst, Amherst, United States
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34
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Abstract
Historically, cell biologists studied organisms that represented a reasonable sampling of life's diversity, whereas recently research has narrowed into a few model systems. As a result, the cells of plants have been relatively neglected. Here I choose three examples to illustrate how plants have been informative and could be even more so. Owing to their ease of imaging and genetic tractability, multicellular plant model systems provide a unique opportunity to address long-standing questions in cell biology.
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Affiliation(s)
- Magdalena Bezanilla
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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35
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Ehrhardt DW, Bezanilla M. Patterning the cell: membrane-cytoskeleton crosstalk. Curr Opin Plant Biol 2013; 16:675-677. [PMID: 24263170 DOI: 10.1016/j.pbi.2013.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- David W Ehrhardt
- Department of Plant Biology, Carnegie Institution for Science, Department of Biology, Stanford University, 260 Panama Street, Stanford, CA 94305, USA.
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36
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van Gisbergen PAC, Bezanilla M. Plant formins: membrane anchors for actin polymerization. Trends Cell Biol 2013; 23:227-33. [PMID: 23317636 DOI: 10.1016/j.tcb.2012.12.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/06/2012] [Accepted: 12/10/2012] [Indexed: 11/18/2022]
Abstract
In plants, the actin cytoskeleton plays a fundamental role in intracellular transport, cell growth, and morphology. Formins are central regulators of actin polymerization and actin-based processes in many eukaryotes. Plants have a diverse family of formins and this diversity arose early in land plant evolution, probably deriving from family expansion and domain acquisition. Recently, formins from different plant lineages have been studied and the focus of these studies is beginning to shift from biochemical characterization to in vivo function. In vivo studies have shown that distinct biochemical activities confer specific cellular functions. Despite these differences, many plant formins have in common a direct link to the plasma membrane, suggesting that formins in plants are important links between the plasma membrane and actin remodeling.
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37
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Abstract
Tip growth is employed throughout the plant kingdom. Our understanding of tip growth has benefited from modern tools in molecular genetics, which have enabled the functional characterization of proteins mediating tip growth. Here we first discuss the evolutionary role of tip growth in land plants and then describe the prominent model tip-growth systems, elaborating on some advantages and disadvantages of each. Next we review the organization of tip-growing cells, the role of the cytoskeleton, and recent developments concerning the physiological basis of tip growth. Finally, we review advances in the understanding of the extracellular signals that are known to guide tip-growing cells.
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Affiliation(s)
- Caleb M Rounds
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
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38
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Vidali L, Bezanilla M. Physcomitrella patens: a model for tip cell growth and differentiation. Curr Opin Plant Biol 2012; 15:625-31. [PMID: 23022392 DOI: 10.1016/j.pbi.2012.09.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/01/2012] [Accepted: 09/04/2012] [Indexed: 05/25/2023]
Abstract
The moss Physcomitrella patens has emerged as an excellent model system owing to its amenability to reverse genetics. The moss gametophyte has three filamentous tissues that grow by tip growth: chloronemata, caulonemata, and rhizoids. Because establishment of the moss plant relies on this form of growth, it is particularly suited for dissecting the molecular basis of tip growth. Recent studies demonstrate that a core set of actin cytoskeletal proteins is essential for tip growth. Additional actin cytoskeletal components are required for modulating growth to produce caulonemata and rhizoids. Differentiation into these cell types has previously been linked to auxin, light and nutrients. Recent studies have identified that core auxin signaling components as well as transcription factors that respond to auxin or nutrient levels are required for tip-growing cell differentiation. Future studies may establish a connection between the actin cytoskeleton and auxin or nutrient-induced cell differentiation.
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Affiliation(s)
- Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, United States
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39
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van Gisbergen PAC, Li M, Wu SZ, Bezanilla M. Class II formin targeting to the cell cortex by binding PI(3,5)P(2) is essential for polarized growth. ACTA ACUST UNITED AC 2012; 198:235-50. [PMID: 22801781 PMCID: PMC3410418 DOI: 10.1083/jcb.201112085] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
PI(3,5)P2 is directly linked to generation and remodeling of the cortical actin array by formin during polarized cell growth in plants. Class II formins are key regulators of actin and are essential for polarized plant cell growth. Here, we show that the class II formin N-terminal phosphatase and tensin (PTEN) domain binds phosphoinositide-3,5-bisphosphate (PI(3,5)P2). Replacing the PTEN domain with polypeptides of known lipid-binding specificity, we show that PI(3,5)P2 binding was required for formin-mediated polarized growth. Via PTEN, formin also localized to the cell apex, phragmoplast, and to the cell cortex as dynamic cortical spots. We show that the cortical localization driven by binding to PI(3,5)P2 was required for function. Silencing the kinases that produce PI(3,5)P2 reduced cortical targeting of formin and inhibited polarized growth. We show a subset of cortical formin spots moved in actin-dependent linear trajectories. We observed that the linearly moving subpopulation of cortical formin generated new actin filaments de novo and along preexisting filaments, providing evidence for formin-mediated actin bundling in vivo. Taken together, our data directly link PI(3,5)P2 to generation and remodeling of the cortical actin array.
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40
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Augustine RC, Pattavina KA, Tüzel E, Vidali L, Bezanilla M. Actin interacting protein1 and actin depolymerizing factor drive rapid actin dynamics in Physcomitrella patens. Plant Cell 2011; 23:3696-710. [PMID: 22003077 PMCID: PMC3229144 DOI: 10.1105/tpc.111.090753] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The remodeling of actin networks is required for a variety of cellular processes in eukaryotes. In plants, several actin binding proteins have been implicated in remodeling cortical actin filaments (F-actin). However, the extent to which these proteins support F-actin dynamics in planta has not been tested. Using reverse genetics, complementation analyses, and cell biological approaches, we assessed the in vivo function of two actin turnover proteins: actin interacting protein1 (AIP1) and actin depolymerizing factor (ADF). We report that AIP1 is a single-copy gene in the moss Physcomitrella patens. AIP1 knockout plants are viable but have reduced expansion of tip-growing cells. AIP1 is diffusely cytosolic and functions in a common genetic pathway with ADF to promote tip growth. Specifically, ADF can partially compensate for loss of AIP1, and AIP1 requires ADF for function. Consistent with a role in actin remodeling, AIP1 knockout lines accumulate F-actin bundles, have fewer dynamic ends, and have reduced severing frequency. Importantly, we demonstrate that AIP1 promotes and ADF is essential for cortical F-actin dynamics.
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Affiliation(s)
- Robert C. Augustine
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
| | - Kelli A. Pattavina
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
| | - Erkan Tüzel
- Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Magdalena Bezanilla
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
- Address correspondence to
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Wu SZ, Ritchie JA, Pan AH, Quatrano RS, Bezanilla M. Myosin VIII regulates protonemal patterning and developmental timing in the moss Physcomitrella patens. Mol Plant 2011; 4:909-21. [PMID: 21873296 DOI: 10.1093/mp/ssr068] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Plants have two classes of myosins. While recent work has focused on class XI myosins showing that myosin XI is responsible for organelle motility and cytoplasmic streaming, much less is known about the role of myosin VIII in plant growth and development. We have used a combination of RNAi and insertional knockouts to probe myosin VIII function in the moss Physcomitrella patens. We isolated Δmyo8ABCDE plants demonstrating that myosin VIII is not required for plant viability. However, myosin VIII mutants are smaller than wild-type plants in part due to a defect in cell size. Additionally, Δmyo8ABCDE plants produce more side branches and form gametophores much earlier than wild-type plants. In the absence of nutrient media, Δmyo8ABCDE plants exhibit significant protonemal patterning defects, including highly curved protonemal filaments, morphologically defective side branches, as well as an increase in the number of branches. Exogenous auxin partially rescues protonemal defects in Δmyo8ABCDE plants grown in the absence of nutrients. This result, together with defects in protonemal branching, smaller caulonemal cells, and accelerated development in the Δmyo8ABCDE plants, suggests that myosin VIII is involved in hormone homeostasis in P. patens.
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Affiliation(s)
- Shu-Zon Wu
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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Li M, van Gisbergen P, Bezanilla M. Phosphoinositide(3,5) bis phosphate is essential for formin-mediated polarized growth. Dev Biol 2011. [DOI: 10.1016/j.ydbio.2011.05.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Although I always knew I wanted to be a scientist, I didn't know I would become a cell biologist. Events in life that you would never have predicted can greatly impact your career trajectory. I have learned to let those events take me in new directions. Following a desire to investigate an understudied area of cell biology, I have found a niche. In this area, my lab is poised to contribute significantly toward understanding the fundamental molecular mechanisms underlying polarized plant cell growth.
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Abstract
The moss Physcomitrella patens has recently emerged as a powerful genetically tractable model plant system. As a member of the bryophytes, P. patens provides a unique opportunity to study the evolution of a myriad of plant traits, such as polarized cell growth, gametophyte-to-sporophyte transitions, and sperm-to-pollen transition. The availability of a complete genome sequence, together with the ability to perform gene targeting efficiently in P. patens has spurred a flurry of elegant reverse genetic studies in this plant model that address a variety of key questions in plant developmental biology.
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Affiliation(s)
- Michael J. Prigge
- Section of Cell and Developmental Biology, University of California, San Diego, CA 92093-0116, USA
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Vidali L, Burkart GM, Augustine RC, Kerdavid E, Tüzel E, Bezanilla M. Myosin XI is essential for tip growth in Physcomitrella patens. Plant Cell 2010; 22:1868-82. [PMID: 20525854 PMCID: PMC2910981 DOI: 10.1105/tpc.109.073288] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 03/29/2010] [Accepted: 05/14/2010] [Indexed: 05/18/2023]
Abstract
Class XI myosins are plant specific and responsible for cytoplasmic streaming. Because of the large number of myosin XI genes in angiosperms, it has been difficult to determine their precise role, particularly with respect to tip growth. The moss Physcomitrella patens provides an ideal system to study myosin XI function. P. patens has only two myosin XI genes, and these genes encode proteins that are 94% identical to each other. To determine their role in tip growth, we used RNA interference to specifically silence each myosin XI gene using 5' untranslated region sequences. We discovered that the two myosin XI genes are functionally redundant, since silencing of either gene does not affect growth or polarity. However, simultaneous silencing of both myosin XIs results in severely stunted plants composed of small rounded cells. Although similar to the phenotype resulting from silencing of other actin-associated proteins, we show that this phenotype is not due to altered actin dynamics. Consistent with a role in tip growth, we show that a functional, full-length fusion of monomeric enhanced green fluorescent protein (mEGFP) to myosin XI accumulates at a subcortical, apical region of actively growing protonemal cells.
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Affiliation(s)
- Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA.
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Vidali L, Augustine RC, Fay SN, Franco P, Pattavina KA, Bezanilla M. Rapid screening for temperature-sensitive alleles in plants. Plant Physiol 2009; 151:506-14. [PMID: 19666707 PMCID: PMC2754644 DOI: 10.1104/pp.109.143727] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 08/06/2009] [Indexed: 05/21/2023]
Abstract
We developed a simple and fast method to identify temperature-sensitive alleles of essential plant genes. We used primary and tertiary structure information to identify residues in the core of the protein of interest. These residues were mutated and tested for temperature sensitivity, taking advantage of the exceptionally rapid 1-week complementation assay in the moss Physcomitrella patens. As test molecules, we selected the actin-binding proteins profilin and actin-depolymerizing factor, because they are essential and their loss-of-function phenotype can be fully rescued. Screening a small number of candidate mutants, we successfully identified temperature-sensitive alleles of both profilin and actin-depolymerizing factor. Plants harboring these alleles grew well at the permissive temperature of 20 degrees C to 25 degrees C but showed a complete loss of function at the restrictive temperature of 32 degrees C. Notably, the profilin mutation identified in the moss gene can be transferred to profilins from other plant species, also rendering them temperature sensitive. The ability to routinely generate temperature-sensitive alleles of essential plant proteins provides a powerful tool for the study of gene function in plants.
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Affiliation(s)
- Luis Vidali
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Vidali L, Rounds CM, Hepler PK, Bezanilla M. Lifeact-mEGFP reveals a dynamic apical F-actin network in tip growing plant cells. PLoS One 2009; 4:e5744. [PMID: 19478943 PMCID: PMC2684639 DOI: 10.1371/journal.pone.0005744] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 05/06/2009] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Actin is essential for tip growth in plants. However, imaging actin in live plant cells has heretofore presented challenges. In previous studies, fluorescent probes derived from actin-binding proteins often alter growth, cause actin bundling and fail to resolve actin microfilaments. METHODOLOGY/PRINCIPAL FINDINGS In this report we use Lifeact-mEGFP, an actin probe that does not affect the dynamics of actin, to visualize actin in the moss Physcomitrella patens and pollen tubes from Lilium formosanum and Nicotiana tobaccum. Lifeact-mEGFP robustly labels actin microfilaments, particularly in the apex, in both moss protonemata and pollen tubes. Lifeact-mEGFP also labels filamentous actin structures in other moss cell types, including cells of the gametophore. CONCLUSIONS/SIGNIFICANCE Lifeact-mEGFP, when expressed at optimal levels does not alter moss protonemal or pollen tube growth. We suggest that Lifeact-mEGFP represents an exciting new versatile probe for further studies of actin's role in tip growing plant cells.
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Affiliation(s)
- Luis Vidali
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Caleb M. Rounds
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Peter K. Hepler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Magdalena Bezanilla
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
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Augustine RC, Vidali L, Kleinman KP, Bezanilla M. Actin depolymerizing factor is essential for viability in plants, and its phosphoregulation is important for tip growth. Plant J 2008; 54:863-75. [PMID: 18298672 DOI: 10.1111/j.1365-313x.2008.03451.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Actin depolymerizing factor (ADF)/cofilin is important for regulating actin dynamics, and in plants is thought to be required for tip growth. However, the degree to which ADF is necessary has been elusive because of the presence of multiple ADF isoforms in many plant species. In the moss Physcomitrella patens, ADF is encoded by a single, intronless gene. We used RNA interference to demonstrate that ADF is essential for plant viability. Loss of ADF dramatically alters the organization of the F-actin cytoskeleton, and leads to an inhibition of tip growth. We show that ADF is subject to phosphorylation in vivo, and using complementation studies we show that mutations of the predicted phosphorylation site partially rescue plant viability, but with differential affects on tip growth. Specifically, the unphosphorylatable ADF S6A mutant generates small polarized plants with normal F-actin organization, whereas the phosphomimetic S6D mutant generates small, unpolarized plants with a disorganized F-actin cytoskeleton. These data indicate that phosphoregulation at serine 6 is required for full ADF function in vivo, and, in particular, that the interaction between ADF and actin is important for tip growth.
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Affiliation(s)
- Robert C Augustine
- Biology Department, University of Massachusetts, Amherst, 611 North Pleasant Street, University of Massachusetts, Amherst, MA 01003-9297, USA
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Vidali L, Augustine RC, Kleinman KP, Bezanilla M. Profilin is essential for tip growth in the moss Physcomitrella patens. Plant Cell 2007; 19:3705-22. [PMID: 17981997 PMCID: PMC2174871 DOI: 10.1105/tpc.107.053413] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 10/05/2007] [Accepted: 10/10/2007] [Indexed: 05/19/2023]
Abstract
The actin cytoskeleton is critical for tip growth in plants. Profilin is the main monomer actin binding protein in plant cells. The moss Physcomitrella patens has three profilin genes, which are monophyletic, suggesting a single ancestor for plant profilins. Here, we used RNA interference (RNAi) to determine the loss-of-function phenotype of profilin. Reduction of profilin leads to a complete loss of tip growth and a partial inhibition of cell division, resulting in plants with small rounded cells and fewer cells. We silenced all profilins by targeting their 3' untranslated region sequences, enabling complementation analyses by expression of profilin coding sequences. We show that any moss or a lily (Lilium longiflorum) profilin support tip growth. Profilin with a mutation in its actin binding site is unable to rescue profilin RNAi, while a mutation in the poly-l-proline binding site weakly rescues. We show that moss tip growing cells contain a prominent subapical cortical F-actin structure composed of parallel actin cables. Cells lacking profilin lose this structure; instead, their F-actin is disorganized and forms polarized cortical patches. Plants expressing the actin and poly-l-proline binding mutants exhibited similar F-actin disorganization. These results demonstrate that profilin and its binding to actin are essential for tip growth. Additionally, profilin is not needed for formation of F-actin, but profilin and its interactions with actin and poly-l-proline ligands are required to properly organize F-actin.
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Affiliation(s)
- Luis Vidali
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Abstract
The haploid gametophyte stage of the moss life cycle is amenable to genetic and biochemical studies. Many species can be cultured on simple defined media, where growth is rapid, making them ideal material for metabolic studies. Developmental responses to hormones and to environmental inputs can be studied both at the level of individual cells and in multicellular tissues. The protonemal stage of gametophyte development comprises cell filaments that extend by the serial division of their apical cells, allowing the investigation of the generation and modification of cell polarity and the role of the cytoskeleton in these processes. Molecular techniques including gene inactivation by targeted gene replacement or by RNA interference, together with the nearly completed sequencing of the Physcomitrella patens genome, open the way for detailed study of the functions of genes involved in both development and metabolism.
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Affiliation(s)
- David Cove
- Center for Plant Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
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