Differential Effect of Plant Lipids on Membrane Organization

• Published in: The Journal of biological chemistry 2015-02, Vol.290 (9), p.5810-5825
• Main Authors: Grosjean, Kevin, Mongrand, Sébastien, Beney, Laurent, Simon-Plas, Françoise, Gerbeau-Pissot, Patricia
• Format: Article
• Language: English
• Subjects: Chemical and Process Engineering; Conjugated Forms of Phytosterol; Engineering Sciences; GIPC; Glycerosphingolipid; Lipid Raft; Liquid Ordered/Disordered Phases; Membrane Reconstitution; Microscopic Imaging; Phospholipid Vesicle; Spatial Distribution of Ordered Domains; Sterol
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M114.598805

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. The effect of the wide variety of plant lipids on membrane organization is still poorly understood. The local amounts of phytosphingolipids and free and conjugated phytosterols control the relative proportion and spatial distribution of ordered domains. Plant lipids differently modulate, alone or in combination, membrane heterogeneity. Our results highlight how plant lipid diversity might drive the plasma membrane subcompartmentalization.