| 1. |
- Mao, Hailiang, et al.
(author)
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Arabidopsis BTB/POZ protein-dependent PENETRATION3 trafficking and disease susceptibility
- 2017
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In: Nature Plants. - : NATURE PUBLISHING GROUP. - 2055-026X .- 2055-0278. ; 3:11, s. 854-858
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Journal article (peer-reviewed)abstract
- The outermost cell layer of plant roots (epidermis) constantly encounters environmental challenges. The epidermal outer plasma membrane domain harbours the PENETRATION3 (PEN3)/ABCG36/PDR8 ATP-binding cassette transporter that confers non-host resistance to several pathogens. Here, we show that the Arabidopsis ENDOPLASMIC RETICULUM-ARRESTED PEN3 (EAP3) BTB/POZ-domain protein specifically mediates PEN3 exit from the endoplasmic reticulum and confers resistance to a root-penetrating fungus, providing prime evidence for BTB/POZ-domain protein-dependent membrane trafficking underlying disease resistance.
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| 2. |
- Nakamura, Moritaka, et al.
(author)
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Auxin and ROP GTPase Signaling of Polar Nuclear Migration in Root Epidermal Hair Cells
- 2018
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In: Plant Physiology. - : American Society of Plant Biologists. - 0032-0889 .- 1532-2548. ; 176:1, s. 378-391
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Journal article (peer-reviewed)abstract
- Polar nuclear migration is crucial during the development of diverse eukaryotes. In plants, root hair growth requires polar nuclear migration into the outgrowing hair. However, knowledge about the dynamics and the regulatory mechanisms underlying nuclear movements in root epidermal cells remains limited. Here, we show that both auxin and Rho-of-Plant (ROP) signaling modulate polar nuclear position at the inner epidermal plasma membrane domain oriented to the cortical cells during cell elongation as well as subsequent polar nuclear movement to the outer domain into the emerging hair bulge in Arabidopsis (Arabidopsis thaliana). Auxin signaling via the nuclear AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and INDOLE ACETIC ACID7 pathway ensures correct nuclear placement toward the inner membrane domain. Moreover, precise inner nuclear placement relies on SPIKE1 Rho-GEF, SUPERCENTIPEDE1 Rho-GDI, and ACTIN7 (ACT7) function and to a lesser extent on VTI11 vacuolar SNARE activity. Strikingly, the directionality and/or velocity of outer polar nuclear migration into the hair outgrowth along actin strands also are ACT7 dependent, auxin sensitive, and regulated by ROP signaling. Thus, our findings provide a founding framework revealing auxin and ROP signaling of inner polar nuclear position with some contribution by vacuolar morphology and of actin-dependent outer polar nuclear migration in root epidermal hair cells.
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| 3. |
- Boutté, Yohann, et al.
(author)
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Cellular processes relying on sterol function in plants
- 2009
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In: Current opinion in plant biology. - : Elsevier BV. - 1369-5266 .- 1879-0356. ; 12:6, s. 705-713
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Journal article (peer-reviewed)abstract
- Sterols are lipophilic membrane components essential for diverse cellular functions. The plant sterol biosynthesis pathway has largely been defined by biochemical approaches. Sterol function has been investigated by the pharmacological and genetic manipulation of sterol biosynthesis. However, mechanisms by which sterols influence cellular processes and targets of sterol function remain largely unknown. During the last two years, new Arabidopsis sterol biosynthesis mutants have been characterized. Their analysis has revealed the contributions of known and alternative routes of sterol biosynthesis to various cellular processes. Subcellular localization and trafficking of a sterol-binding protein have been investigated and first steps towards in vivo characterization of sterol-enriched membrane domains have been taken. Finally, mechanistic insight into the role of plant sterols during endocytosis and the establishment of cell polarity has been obtained.
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| 4. |
- Boutté, Yohann, et al.
(author)
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Endocytosis restricts Arabidopsis KNOLLE syntaxin to the cell division plane during late cytokinesis
- 2010
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In: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 29:3, s. 546-58
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Journal article (peer-reviewed)abstract
- Cytokinesis represents the final stage of eukaryotic cell division during which the cytoplasm becomes partitioned between daughter cells. The process differs to some extent between animal and plant cells, but proteins of the syntaxin family mediate membrane fusion in the plane of cell division in diverse organisms. How syntaxin localization is kept in check remains elusive. Here, we report that localization of the Arabidopsis KNOLLE syntaxin in the plane of cell division is maintained by sterol-dependent endocytosis involving a clathrin- and DYNAMIN-RELATED PROTEIN1A-dependent mechanism. On genetic or pharmacological interference with endocytosis, KNOLLE mis-localizes to lateral plasma membranes after cell-plate fusion. Fluorescence-loss-in-photo-bleaching and fluorescence-recovery-after-photo-bleaching experiments reveal lateral diffusion of GFP-KNOLLE from the plane of division to lateral membranes. In an endocytosis-defective sterol biosynthesis mutant displaying lateral KNOLLE diffusion, KNOLLE secretory trafficking remains unaffected. Thus, restriction of lateral diffusion by endocytosis may serve to maintain specificity of syntaxin localization during late cytokinesis.
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| 5. |
- Boutté, Yohann, et al.
(author)
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Fluorescent in situ visualization of sterols in Arabidopsis roots
- 2011
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In: Nature Protocols. - : Springer Science and Business Media LLC. - 1754-2189 .- 1750-2799. ; 6:4, s. 446-456
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Journal article (peer-reviewed)abstract
- Sterols are eukaryotic membrane components with crucial roles in diverse cellular processes. Elucidation of sterol function relies on development of tools for in situ sterol visualization. Here we describe protocols for in situ sterol localization in Arabidopsis thaliana root cells, using filipin as a specific probe for detection of fluorescent filipin-sterol complexes. Currently, filipin is the only established tool for sterol visualization in plants. Filipin labeling can be performed on aldehyde-fixed samples, largely preserving fluorescent proteins and being compatible with immunocytochemistry. Filipin can also be applied for probing live cells, taking into account the fact that it inhibits sterol-dependent endocytosis. The experimental procedures described are designed for fluorescence detection by confocal laser-scanning microscopy with excitation of filipin-sterol complexes at 364 nm. The protocols require 1 d for sterol covisualization with fluorescent proteins in fixed or live roots and 2 d for immunocytochemistry on whole-mount roots.
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| 6. |
- Boutté, Yohann, et al.
(author)
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Immunocytochemical fluorescent in situ visualization of proteins in Arabidopsis
- 2014
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In: Arabidopsis protocols. - Totowa, NJ : Humana Press. ; 1062:1062, s. 453-472
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Book chapter (peer-reviewed)abstract
- The understanding of cellular and subcellular functions often relies on the ability to visualize proteins as close as possible to their endogenous locations. A number of immunocytochemical techniques have been developed to detect proteins in situ using specific antibodies raised against proteins of interest. Here, we describe in detail two protocols commonly, successfully employed in Arabidopsis research. The first allows for immunolocalization of proteins in whole-mount Arabidopsis roots without the need for physical sectioning. The second allows for immunolocalization of proteins on semi-thin microtome sections of wax-embedded swamples. This approach is particularly useful when sectioning of Arabidopsis roots or other thicker plant organs is required for immunolocalization. We provide step-by-step protocols with extensive troubleshooting for both the whole-mount and sectioning protocols. Furthermore, critical steps, advantages, and limitations of the two protocols described here are discussed.
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| 7. |
- Boutté, Yohann, et al.
(author)
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Mechanisms of auxin-dependent cell and tissue polarity
- 2007
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In: Current opinion in plant biology. - : Elsevier. - 1369-5266 .- 1879-0356. ; 10:6, s. 616-623
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Journal article (peer-reviewed)abstract
- The establishment of cellular asymmetries and their coordination within the tissue layer are fundamental to the development of multicellular organisms. In plants, the induction and coordination of cell polarity have classically been attributed to involve the hormone auxin and its flow. However, the underlying mechanisms have only recently been addressed at the molecular level. We review progress on the characterisation of the auxin influx and efflux carrier properties of specific plasma membrane proteins, mechanisms underlying their delivery to and internalisation from the plasma membrane, their endocytic transport and degradation. We discuss mechanisms of auxin gradient, transport and response action during the coordination of polarity, along with the downstream involvement of Rho-of-plant small GTPases during the execution of cell polarity.
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| 8. |
- de la Presilla, Roman José, et al.
(author)
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Oscillating rolling element bearings : A review of tribotesting and analysis approaches
- 2023
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In: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 188
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Research review (peer-reviewed)abstract
- Rolling element bearings, when subjected to small oscillating movements or vibrations, run the risk of being damaged by mechanisms such as Standstill Marks and False Brinelling. Damages resulting from these phenomena can decrease bearing fatigue life and increase wear-induced friction torque. These failures do not correlate well with standard life estimation approaches. Experimental studies play a crucial role in gaining knowledge in this area. The review integrates knowledge from experiments ranging from single contacts to laboratory and full-scale bearings in wind power and aerospace applications. The generalization is achieved using a non-dimensional amplitude parameter that relates rolling element travel during an oscillation to the Hertzian contact size. The review encompasses testing methods, procedures, reporting practices, result scaling, and application-specific considerations.
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| 9. |
- Fischer, Urs, et al.
(author)
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Lipid function in plant cell polarity.
- 2004
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In: Current opinion in plant biology. - : Elsevier BV. - 1369-5266 .- 1879-0356. ; 7:6, s. 670-6
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Journal article (peer-reviewed)abstract
- The establishment and maintenance of cell polarity play pivotal roles during plant development. During the past five years, proteins that are required for different aspects of plant cell polarity have been identified. However, the functions of lipids and their interactions with proteins that mediate polarity remained largely unaddressed. Recent genetic studies have discovered cell and tissue polarity mutants that have defects in sterol composition, glycosylphosphatidylinositol-anchored proteins, glycosylphosphatidylinositol biosynthesis and phospholipid signalling. Analyses of the affected gene products have provided a first glance at the roles of lipids in cell polarity signalling, as well as in the trafficking and anchoring of polar proteins.
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| 10. |
- Fischer, Urs, et al.
(author)
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Planar polarity of root hair positioning in Arabidopsis
- 2007
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In: Biochemical Society Transactions. - 0300-5127 .- 1470-8752. ; 35:Pt 1, s. 149-151
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Journal article (peer-reviewed)abstract
- The co-ordinated polarity of cells within the plane of a single tissue layer (planar polarity) is intensively studied in animal epithelia but has only recently been systematically analysed in plants. The polar positioning of hairs in the root epidermis of Arabidopsis thaliana provides an easily accessible system for the functional dissection of a plant-specific planar polarity. Recently, mutants originally isolated in genetic screens for defects in root hair morphogenesis and changes in the sensitivity to or the production of the plant hormones auxin and ethylene have identified players that contribute to polar root hair placement. Here, we summarize and discuss recent progress in research on polar root hair positioning from studies in Arabidopsis.
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