0000000001219040
AUTHOR
Sebastien Mongrand
Influence of phytosterols on the structural and dynamic properties of plant plasma membrane
National audience; The complex mixture of sterols, namely phytosterols, found in the plasma membrane (PM) of plant cells is an intriguing characteristic. In the present work, we characterized the sterol composition of tobacco BY-2 cell PM, and we adapted a sterol manipulation method to this plant material. Methyl-b-cyclodextrin was found to induce a drastic reduction of the PM total free sterol content, with a low specificity for the different phytosterols, and without effect on steryl-conjugates. The consequences of phytosterols depletion were investigated by means of fluorescence spectroscopy and biochemical detergent resistant membrane (DRM) fraction purification methods. Data obtained w…
Liquid ordered domains of tobacco cell plasma membrane : in vivo visualization, spatial distribution and modulation upon elicitation
SPE IPM; International audience; The ability of lipids in complex mixtures to form liquid-ordered, sterol-rich phases, together with the association of specific proteins with sterol-enriched biochemical fractions extracted from biological membranes, gave raise to the "lipid rafts" hypothesis. This suggests the presence within biological membranes of small-sized, ordered domains, of particular lipid and protein composition, which could serve as signal transduction platforms, particularly during plant-microorganisms interactions. However, the precise organization of living cell plasma membrane is still poorly described and the spatial distribution of segregating liquid-disordered and liquid-o…
Plant lipids: Key players of plasma membrane organization and function
International audience; The Plasma Membrane (PM) is a key structure protecting the cell, regulating nutrient exchanges and acting as a control tower allowing the cell to perceive signals. Plasma comes from the greek πλάσμα meaning "which molds", meaning that the PM takes the shape of the cell by delimitating it. The PM harbors the appropriate signaling cascades allowing adaptive responses ensuring proper cell functions in a continuously fluctuating environment, crucial for cell survival. To address this challenge, the PM needs to be both stable and robust yet incredibly fluid and adaptable. This amazing combination of long-term stability and short-term dynamics in order to adapt to signals …
Plasma membrane microdomains in plants: for which physiological roles?
International audience; A large body of evidence supports the existence, in membrane from animal and yeast cells, of functional microdomains playing important roles in protein sorting, signal transduction, or infection by pathogens (1). We demonstrated the presence, in plants, of detergent resistant fractions isolated from plasma membrane, with a lipidic composition similar to animal microdomains (2). Electrophoresis experiments indicated that these fractions were able to recruit a specific set of plasma membrane proteins and exclude others. We used mass spectrometry to give an extensive description of a tobacco plasma membrane microdomains. This led to the identification of 145 proteins wh…