High Lipid Order of Arabidopsis Cell Plate Membranes Mediated by Sterol and DYNAMIN-RELATED PROTEIN1A Function
Plant J. 2014, 80(5):745-757
Frescatada-Rosa M, Stanislas T, Backues SK, Reichardt I, Men S, Boutté Y, Jürgens G, Moritz T, Bednarek SY, Grebe M

Abstract
Membranes of eukaryotic cells contain high-lipid-order, sterol-rich domains thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components remain unaddressed during eukaryotic cytokinesis. Here we show by employing ratiometric live imaging of lipid order-sensitive fluorescent probes that the cell plate of Arabidopsis thaliana represents a dynamic, high-lipid-order membrane domain. Cell plate lipid order proves sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high-lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high-lipid-order domain and pave the way to explore potential feedback between lipid order and DRP protein function during cytokinesis.

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