The Experts below are selected from a list of 2082 Experts worldwide ranked by ideXlab platform
Zhenbiao Yang - One of the best experts on this subject based on the ideXlab platform.
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the microtubule associated protein iq67 domain5 modulates microtubule dynamics and Pavement cell shape
Plant Physiology, 2018Co-Authors: Yi Zhang, Hong Liang, Pablo Martinez, Carolyn G Rasmussen, Zhenbiao YangAbstract:The dynamic arrangement of cortical microtubules (MTs) plays a pivotal role in controlling cell growth and shape formation in plants, but the mechanisms by which cortical MTs are organized to regulate these processes are not well characterized. In particular, the dynamic behavior of cortical MTs is critical for their spatial organization, yet the molecular mechanisms controlling MT dynamics remain poorly understood. In this study, we used the puzzle piece-shaped Pavement Cells of Arabidopsis (Arabidopsis thaliana) leaves as a model system in which to study cortical MT organization. We isolated an ethyl methanesulfonate mutant with reduced interdigitation of Pavement Cells in cotyledons. This line carried a mutation in IQ67 DOMAIN5 (IQD5), which encodes a member of the plant-specific IQ motif protein family. Live-cell imaging and biochemical analyses demonstrated that IQD5 binds to MTs and promotes MT assembly. MT-depolymerizing drug treatment and in vivo MT dynamics assays suggested that IQD5 functions to stabilize MTs. Hence, our findings provide genetic, cell biological, and biochemical evidence that IQD5 regulates MT dynamics that affect MT organization and subsequent cell shape formation.
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signalling and crosstalks
2016Co-Authors: Jisheng Chen, Fei Wang, Shiqin Zheng, Zhenbiao YangAbstract:Pavement Cells: a model system for non-transcriptional auxi
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rop gtpase dependent actin microfilaments promote pin1 polarization by localized inhibition of clathrin dependent endocytosis
PLOS Biology, 2012Co-Authors: Shingo Nagawa, Deshu Lin, Pankaj Dhonukshe, Xingxing Zhang, Jiri Friml, Ben Scheres, Zhenbiao YangAbstract:Cell polarization via asymmetrical distribution of structures or molecules is essential for diverse cellular functions and development of organisms, but how polarity is developmentally controlled has been poorly understood. In plants, the asymmetrical distribution of the PIN-FORMED (PIN) proteins involved in the cellular efflux of the quintessential phytohormone auxin plays a central role in developmental patterning, morphogenesis, and differential growth. Recently we showed that auxin promotes cell interdigitation by activating the Rho family ROP GTPases in leaf epidermal Pavement Cells. Here we found that auxin activation of the ROP2 signaling pathway regulates the asymmetric distribution of PIN1 by inhibiting its endocytosis. ROP2 inhibits PIN1 endocytosis via the accumulation of cortical actin microfilaments induced by the ROP2 effector protein RIC4. Our findings suggest a link between the developmental auxin signal and polar PIN1 distribution via Rho-dependent cytoskeletal reorganization and reveal the conservation of a design principle for cell polarization that is based on Rho GTPase-mediated inhibition of endocytosis.
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uniform auxin triggers the rho gtpase dependent formation of interdigitation patterns in Pavement Cells
Small GTPases, 2011Co-Authors: Shingo Nagawa, Zhenbiao YangAbstract:The investigation of Rho-family GTPases has uncovered mechanisms for spatiotemporal control of cellular processes such as cell polarization, movement, morphogenesis, and cell division. Now Rho GTPase plays another leading role in the discovery of a new signaling mechanism for auxin, a multi-functional hormone that regulates pattern formation in plants. Arabidopsis leaf epidermal Pavement Cells (PCs) develop the puzzle-piece cell shape with interlocking lobes and indentations via interdigitated cellular growth.1 Through the ABP1 (Auxin Binding Protein 1) cell surface receptor, auxin coordinately activates two mutually exclusive Rho GTPase signaling pathways that are activated in the complementary lobing and indenting sides of adjacent Cells: the ROP2 pathway for lobe formation and the ROP6 pathway for promoting indentation. This new signaling mechanism also involves ROP2-dependent polar accumulation of PIN1 in the plasma membrane, a member of the PIN auxin efflux carrier family that is critical for the for...
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Cell surface- and rho GTPase-based auxin signaling controls cellular interdigitation in Arabidopsis.
Cell, 2010Co-Authors: Tongda Xu, Jin-gui Chen, Shingo Nagawa, Catherine Perrot-rechenmann, Ming Jing Wu, Alan M. Jones, Ying Fu, Zhenbiao YangAbstract:Auxin is a multifunctional hormone essential for plant development and pattern formation. A nuclear auxin-signaling system controlling auxin-induced gene expression is well established, but cytoplasmic auxin signaling, as in its coordination of cell polarization, is unexplored. We found a cytoplasmic auxin-signaling mechanism that modulates the interdigitated growth of Arabidopsis leaf epidermal Pavement Cells (PCs), which develop interdigitated lobes and indentations to form a puzzle-piece shape in a two-dimensional plane. PC interdigitation is compromised in leaves deficient in either auxin biosynthesis or its export mediated by PINFORMED 1 localized at the lobe tip. Auxin coordinately activates two Rho GTPases, ROP2 and ROP6, which promote the formation of complementary lobes and indentations, respectively. Activation of these ROPs by auxin occurs within 30 s and depends on AUXIN-BINDING PROTEIN 1. These findings reveal Rho GTPase-based auxin-signaling mechanisms, which modulate the spatial coordination of cell expansion across a field of Cells.
Henrik Jönsson - One of the best experts on this subject based on the ideXlab platform.
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Mechanochemical polarization of contiguous cell walls shapes plant Pavement Cells
Developmental Cell, 2017Co-Authors: Mateusz Majda, Peter Grones, Ida-maria Sintorn, Thomas Vain, Pascale Milani, Pawel Krupinski, Beata Zagórska-marek, Corrado Viotti, Henrik Jönsson, Ewa J. MellerowiczAbstract:The epidermis of aerial plant organs is thought to be limiting for growth, because it acts as a continuous load-bearing layer, resisting tension. Leaf epidermis contains jigsaw puzzle piece-shaped Pavement Cells whose shape has been proposed to be a result of subcellular variations in expansion rate that induce local buckling events. Paradoxically, such local compressive buckling should not occur given the tensile stresses across the epidermis. Using computational modeling, we show that the simplest scenario to explain Pavement cell shapes within an epidermis under tension must involve mechanical wall heterogeneities across and along the anticlinal Pavement cell walls between adjacent Cells. Combining genetics, atomic force microscopy, and immunolabeling, we demonstrate that contiguous cell walls indeed exhibit hybrid mechanochemical properties. Such biochemical wall heterogeneities precede wall bending. Altogether, this provides a possible mechanism for the generation of complex plant cell shapes.
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subcellular and supracellular mechanical stress prescribes cytoskeleton behavior in arabidopsis cotyledon Pavement Cells
eLife, 2014Co-Authors: Pascale Milani, Pawel Krupinski, Henrik Jönsson, Arun Sampathkumar, Raymond Wightman, Alexandre Berquand, Arezki Boudaoud, Olivier HamantAbstract:The surfaces of plants are covered in epithelial Cells that come in many different shapes, suggesting that individual Cells must have some control over their own shape. An unusually shaped epithelial cell is the Pavement cell, which looks like a jigsaw puzzle piece and is found in the leaves of many flowering plants. Relatively little was known about the exact contribution of mechanical properties of the wall to this shape. Furthermore, although it was known that parts of Pavement Cells are rich in microtubules—tubes of protein that act as a scaffold inside the cell— the possibility that shape impacts the behavior of microtubules was not fully addressed. Now, using a combination of computer modelling and experiments, Sampathkumar et al. reveal that the shape of the Pavement Cells relies in part on the response of the microtubules to stress. In an individual cell, microtubules align along the direction of the largest stress, with a protein severing those microtubules that are not aligned in this direction. As the stress inside a cell is determined in part by the cell’s shape, this sets up a feedback loop: the stress resulting from the cell shape aligns the microtubules that reinforce the cell wall, thus maintaining the shape of the cell. An external stress applied to the epithelium can override this internal stress. Because all of the plant Cells are under turgor pressure from the inside, pressure from the outside, like squeezing a balloon, changes the stress pattern, causing the realignment of the microtubules so as to resist the new stress. This shows that the microtubules respond to local stresses within a cell, and are continually responsive to stress changes.
Steffen Abel - One of the best experts on this subject based on the ideXlab platform.
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microtubule associated protein iq67 domain5 regulates morphogenesis of leaf Pavement Cells in arabidopsis thaliana
Journal of Experimental Botany, 2019Co-Authors: Dipannita Mitra, Sandra Klemm, Pratibha Kumari, Jakob Quegwer, Birgit Moller, Yvonne Poeschl, Paul Pflug, Gina Stamm, Steffen AbelAbstract:Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation, and cell morphology. Their organization and dynamics are co-ordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization, and biological functions. We show that IQD5 is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis of iqd5 loss-of-function lines reveals functions of IQD5 in Pavement cell (PC) shape morphogenesis. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced anisotropic expansion. Lastly, we demonstrate IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays and provide first evidence for important roles for calcium in regulation of PC morphogenesis. Our work identifies IQD5 as a novel player in PC shape regulation and, for the first time, links calcium signaling to developmental processes that regulate anisotropic growth in PCs.
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microtubule associated protein iq67 domain5 regulates interdigitation of leaf Pavement Cells in arabidopsis thaliana
bioRxiv, 2018Co-Authors: Dipannita Mitra, Sandra Klemm, Pratibha Kumari, Jakob Quegwer, Yvonne Poeschl, Paul Pflug, Gina Stamm, Steffen Abel, Birgit MoellerAbstract:Abstract Plant microtubules form a highly dynamic intracellular network with important roles for regulating cell division, cell proliferation and cell morphology. Its organization and dynamics are coordinated by various microtubule-associated proteins (MAPs) that integrate environmental and developmental stimuli to fine-tune and adjust cytoskeletal arrays. IQ67 DOMAIN (IQD) proteins recently emerged as a class of plant-specific MAPs with largely unknown functions. Here, using a reverse genetics approach, we characterize Arabidopsis IQD5 in terms of its expression domains, subcellular localization and biological functions. We show that IQD5 is expressed mostly in vegetative tissues, where it localizes to cortical microtubule arrays. Our phenotypic analysis of iqd5 loss-of-function lines reveals functions of IQD5 in Pavement cell (PC) shape morphogenesis, as indicated by reduced interdigitation of neighboring Cells in the leaf epidermis of iqd5 mutants. Histochemical analysis of cell wall composition further suggests reduced rates of cellulose deposition in anticlinal cell walls, which correlate with reduced asymmetric expansion. Lastly, we provide evidence for IQD5-dependent recruitment of calmodulin calcium sensors to cortical microtubule arrays. Our work thus identifies IQD5 as a novel player in PC shape regulation, and, for the first time, links calcium signaling to developmental processes that regulate multi-polar growth in PCs. Highlight Microtubule-localized Arabidopsis IQ67 DOMAIN5 regulates Pavement cell morphogenesis in the leaf epidermis and links calcium-calmodulin signaling to lobe initiation and asymmetric expansion during early phases of interdigitated cell growth.
Hongwei Xue - One of the best experts on this subject based on the ideXlab platform.
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rice microtubule associated protein iq67 domain14 regulates grain shape by modulating microtubule cytoskeleton dynamics
Plant Biotechnology Journal, 2020Co-Authors: Baojun Yang, Jos R Wendrich, Bert De Rybel, Dolf Weijers, Hongwei XueAbstract:Cortical microtubule (MT) arrays play a critical role in plant cell shape determination by defining the direction of cell expansion. As plants continuously adapt to ever-changing environmental conditions, multiple environmental and developmental inputs need to be translated into changes of the MT cytoskeleton. Here, we identify and functionally characterize an auxin-inducible and MT-localized protein OsIQ67-DOMAIN14 (OsIQD14), which is highly expressed in rice seed hull Cells. We show that while deficiency of OsIQD14 results in short and wide seeds and increases overall yield, overexpression leads to narrow and long seeds, caused by changed MT alignment. We further show that OsIQD14-mediated MT reordering is regulated by specifically affecting MT dynamics, and ectopic expression of OsIQD14 in Arabidopsis could change the cell shape both in Pavement Cells and in hypocotyl Cells. Additionally, OsIQD14 activity is tightly controlled by calmodulin proteins, providing an alternative way to modify the OsIQD14 activity. Our results indicate that OsIQD14 acts as a key factor in regulating MT rearrangements in rice hull Cells and hence the grain shape, and allows effective local cell shape manipulation to improve the rice yield trait.
Takumi Higaki - One of the best experts on this subject based on the ideXlab platform.
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basic proline rich protein mediated microtubules are essential for lobe growth and flattened cell geometry
Plant Physiology, 2019Co-Authors: Jeh Haur Wong, Takumi Higaki, Takehide Kato, Samuel A Belteton, Rie Shimizu, Nene Kinoshita, Yuichi Sakumura, Daniel B Szymanski, Takashi HashimotoAbstract:Complex cell shapes are generated first by breaking symmetry, and subsequent polar growth. Localized bending of anticlinal walls initiates lobe formation in the epidermal Pavement Cells of cotyledons and leaves, but how the microtubule cytoskeleton mediates local cell growth, and how plant Pavement Cells benefit from adopting jigsaw puzzle-like shapes, are poorly understood. In Arabidopsis (Arabidopsis thaliana), the basic Pro-rich protein (BPP) microtubule-associated protein family comprises seven members. We analyzed lobe morphogenesis in cotyledon Pavement Cells of a BPP1;BPP2;BPP5 triple knockout mutant. New image analysis methods (MtCurv and BQuant) showed that anticlinal microtubule bundles were significantly reduced and cortical microtubules that fan out radially across the periclinal wall did not enrich at the convex side of developing lobes. Despite these microtubule defects, new lobes were initiated at the same frequency as in wild-type Cells, but they did not expand into well-defined protrusions. Eventually, mutant Cells formed nearly polygonal shapes and adopted concentric microtubule patterns. The mutant periclinal cell wall bulged outward. The radius of the calculated inscribed circle of the Pavement Cells, a proposed proxy for maximal stress in the cell wall, was consistently larger in the mutant Cells during cotyledon development, and correlated with an increase in cell height. These bpp mutant phenotypes provide genetic and cell biological evidence that initiation and growth of lobes are distinct morphogenetic processes, and that interdigitated cell geometry effectively suppresses large outward bulging of Pavement Cells.
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cell wall accumulation of fluorescent proteins derived from a trans golgi cisternal membrane marker and paramural bodies in interdigitated arabidopsis leaf epidermal Cells
Protoplasma, 2017Co-Authors: Kae Akita, Megumi Kobayashi, Mayuko Sato, Natsumaro Kutsuna, Takashi Ueda, Kiminori Toyooka, Noriko Nagata, Seiichiro Hasezawa, Takumi HigakiAbstract:In most dicotyledonous plants, leaf epidermal Pavement Cells develop jigsaw puzzle-like shapes during cell expansion. The rapid growth and complicated cell shape of Pavement Cells is suggested to be achieved by targeted exocytosis that is coordinated with cytoskeletal rearrangement to provide plasma membrane and/or cell wall materials for lobe development during their morphogenesis. Therefore, visualization of membrane trafficking in leaf Pavement Cells should contribute an understanding of the mechanism of plant cell morphogenesis. To reveal membrane trafficking in Pavement Cells, we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes, in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of Pavement cell borders and guard cell ends during leaf expansion. Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated Pavement Cells and guard cell ends in young leaf epidermis. In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes. These results suggested possible heterogeneity of the curved regions of plasma membranes, implying a relationship with Pavement cell morphogenesis.
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quantitative analysis of microtubule orientation in interdigitated leaf Pavement Cells
Plant Signaling & Behavior, 2015Co-Authors: Kae Akita, Natsumaro Kutsuna, Takumi Higaki, Seiichiro HasezawaAbstract:Leaf Pavement Cells are shaped like a jigsaw puzzle in most dicotyledon species. Molecular genetic studies have identified several genes required for Pavement Cells morphogenesis and proposed that microtubules play crucial roles in the interdigitation of Pavement Cells. In this study, we performed quantitative analysis of cortical microtubule orientation in leaf Pavement Cells in Arabidopsis thaliana. We captured confocal images of cortical microtubules in cotyledon leaf epidermis expressing GFP-tubulinβ and quantitatively evaluated the microtubule orientations relative to the Pavement cell growth axis using original image processing techniques. Our results showed that microtubules kept parallel orientations to the growth axis during Pavement cell growth. In addition, we showed that immersion treatment of seed cotyledons in solutions containing tubulin polymerization and depolymerization inhibitors decreased Pavement cell complexity. Treatment with oryzalin and colchicine inhibited the symmetric division of guard mother Cells.