2018
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Interactions between lipids and proteins are critical for organization of plasma membrane-ordered domains in tobacco BY-2 cells Article de journal K Grosjean; C Der; F Robert; D Thomas; S Mongrand; F Simon-Plas; P Gerbeau-Pissot Journal of Experimental Botany, 69 (15), p. 3545–3557, 2018. @article{Grosjean:2018,
title = {Interactions between lipids and proteins are critical for organization of plasma membrane-ordered domains in tobacco BY-2 cells},
author = {K Grosjean and C Der and F Robert and D Thomas and S Mongrand and F Simon-Plas and P Gerbeau-Pissot},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050850362&doi=10.1093%2fjxb%2fery152&partnerID=40&md5=1bc7ac85ba1b255cd33e4b374af4cbb2},
doi = {10.1093/jxb/ery152},
year = {2018},
date = {2018-01-01},
journal = {Journal of Experimental Botany},
volume = {69},
number = {15},
pages = {3545--3557},
abstract = {The laterally heterogeneous plant plasma membrane (PM) is organized into finely controlled specialized areas that include membrane-ordered domains. Recently, the spatial distribution of such domains within the PM has been identified as playing a key role in cell responses to environmental challenges. To examine membrane order at a local level, BY-2 tobacco suspension cell PMs were labelled with an environment-sensitive probe (di-4-ANEPPDHQ). Four experimental models were compared to identify mechanisms and cell components involved in short-term (1 h) maintenance of the ordered domain organization in steady-state cell PMs: modulation of the cytoskeleton or the cell wall integrity of tobacco BY-2 cells; and formation of giant vesicles using either a lipid mixture of tobacco BY-2 cell PMs or the original lipid and protein combinations of the tobacco BY-2 cell PM. Whilst inhibiting phosphorylation or disrupting either the cytoskeleton or the cell wall had no observable effects, we found that lipids and proteins significantly modified both the abundance and spatial distribution of ordered domains. This indicates the involvement of intrinsic membrane components in the local physical state of the plant PM. Our findings support a major role for the 'lipid raft' model, defined as the sterol-dependent ordered assemblies of specific lipids and proteins in plant PM organization. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The laterally heterogeneous plant plasma membrane (PM) is organized into finely controlled specialized areas that include membrane-ordered domains. Recently, the spatial distribution of such domains within the PM has been identified as playing a key role in cell responses to environmental challenges. To examine membrane order at a local level, BY-2 tobacco suspension cell PMs were labelled with an environment-sensitive probe (di-4-ANEPPDHQ). Four experimental models were compared to identify mechanisms and cell components involved in short-term (1 h) maintenance of the ordered domain organization in steady-state cell PMs: modulation of the cytoskeleton or the cell wall integrity of tobacco BY-2 cells; and formation of giant vesicles using either a lipid mixture of tobacco BY-2 cell PMs or the original lipid and protein combinations of the tobacco BY-2 cell PM. Whilst inhibiting phosphorylation or disrupting either the cytoskeleton or the cell wall had no observable effects, we found that lipids and proteins significantly modified both the abundance and spatial distribution of ordered domains. This indicates the involvement of intrinsic membrane components in the local physical state of the plant PM. Our findings support a major role for the 'lipid raft' model, defined as the sterol-dependent ordered assemblies of specific lipids and proteins in plant PM organization. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. |
2016
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Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride Article de journal B Grosjean; C Pean; A Siria; L Bocquet; R Vuilleumier; M -L Bocquet Journal of Physical Chemistry Letters, 7 (22), p. 4695–4700, 2016. @article{Grosjean:2016,
title = {Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride},
author = {B Grosjean and C Pean and A Siria and L Bocquet and R Vuilleumier and M -L Bocquet},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84996563991&doi=10.1021%2facs.jpclett.6b02248&partnerID=40&md5=c996527c2b197c80bcb105d4176e42c9},
doi = {10.1021/acs.jpclett.6b02248},
year = {2016},
date = {2016-01-01},
journal = {Journal of Physical Chemistry Letters},
volume = {7},
number = {22},
pages = {4695--4700},
abstract = {Recent nanofluidic experiments revealed strongly different surface charge measurements for boron-nitride (BN) and graphitic nanotubes when in contact with saline and alkaline water (Nature 2013, 494, 455-458; Phys. Rev. Lett. 2016, 116, 154501). These observations contrast with the similar reactivity of a graphene layer and its BN counterpart, using density functional theory (DFT) framework, for intact and dissociative adsorption of gaseous water molecules. Here we investigate, by DFT in implicit water, single and multiple adsorption of anionic hydroxide on single layers. A differential adsorption strength is found in vacuum for the first ionic adsorption on the two materials - chemisorbed on BN while physisorbed on graphene. The effect of implicit solvation reduces all adsorption values, resulting in a favorable (nonfavorable) adsorption on BN (graphene). We also calculate a pKa ≃ 6 for BN in water, in good agreement with experiments. Comparatively, the unfavorable results for graphene in water echo the weaker surface charge measurements but point to an alternative scenario. © 2016 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recent nanofluidic experiments revealed strongly different surface charge measurements for boron-nitride (BN) and graphitic nanotubes when in contact with saline and alkaline water (Nature 2013, 494, 455-458; Phys. Rev. Lett. 2016, 116, 154501). These observations contrast with the similar reactivity of a graphene layer and its BN counterpart, using density functional theory (DFT) framework, for intact and dissociative adsorption of gaseous water molecules. Here we investigate, by DFT in implicit water, single and multiple adsorption of anionic hydroxide on single layers. A differential adsorption strength is found in vacuum for the first ionic adsorption on the two materials - chemisorbed on BN while physisorbed on graphene. The effect of implicit solvation reduces all adsorption values, resulting in a favorable (nonfavorable) adsorption on BN (graphene). We also calculate a pKa ≃ 6 for BN in water, in good agreement with experiments. Comparatively, the unfavorable results for graphene in water echo the weaker surface charge measurements but point to an alternative scenario. © 2016 American Chemical Society. |
2015
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Differential effect of plant lipids on membrane organization specificities of phytosphingolipids and phytosterols Article de journal K Grosjean; S Mongrand; L Beney; F Simon-Plas; P Gerbeau-Pissot Journal of Biological Chemistry, 290 (9), p. 5810–5825, 2015. @article{Grosjean:2015,
title = {Differential effect of plant lipids on membrane organization specificities of phytosphingolipids and phytosterols},
author = {K Grosjean and S Mongrand and L Beney and F Simon-Plas and P Gerbeau-Pissot},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923788813&doi=10.1074%2fjbc.M114.598805&partnerID=40&md5=6977c0323a159b8a5efec40d787b4573},
doi = {10.1074/jbc.M114.598805},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biological Chemistry},
volume = {290},
number = {9},
pages = {5810--5825},
abstract = {The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains. © 2015 by The American Society for Biochemistry and Molecular Biology Inc.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains. © 2015 by The American Society for Biochemistry and Molecular Biology Inc. |
