Recycling,clustering, and endocytosis jointly maintain PIN auxin carrier polarity at the plasma membrane |
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Authors: | Alexandre Martinière ?ukasz ?angowski Katrin Willig Satoshi Naramoto Johannes Leitner Hirokazu Tanaka Stefan Jakobs Stéphanie Robert Christian Luschnig Willy Govaerts Stefan W Hell John Runions Ji?í Friml |
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Institution: | 1. Department of Biological and Medical Sciences, School of Life Sciences, Oxford Brookes University, , Oxford, UK;2. Department of Plant Systems Biology, VIB, Universiteit Gent, , Gent, Belgium;3. Department of Plant Biotechnology and Genetics, Ghent University, , Gent, Belgium;4. Department of NanoBiophotonics and DFG‐Research Center for Molecular Physiology of the Brain, Max Planck Institute for Biophysical Chemistry, , G?ttingen, Germany;5. Department of Applied Genetics and Cell Biology, University of Applied Life Sciences and Natural Resources (BOKU), , Vienna, Austria;6. Department of Biological Science, Graduate School of Science, Osaka University, , Osaka, Japan;7. Department of Forest Genetics and Plant Physiology, Ume? Plant Science Centre, Swedish University of Agricultural Sciences, , Ume?, Sweden;8. Department of Applied Mathematics and Computer Science, Ghent University, , Gent, Belgium |
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Abstract: | Cell polarity reflected by asymmetric distribution of proteins at the plasma membrane is a fundamental feature of unicellular and multicellular organisms. It remains conceptually unclear how cell polarity is kept in cell wall‐encapsulated plant cells. We have used super‐resolution and semi‐quantitative live‐cell imaging in combination with pharmacological, genetic, and computational approaches to reveal insights into the mechanism of cell polarity maintenance in Arabidopsis thaliana. We show that polar‐competent PIN transporters for the phytohormone auxin are delivered to the center of polar domains by super‐polar recycling. Within the plasma membrane, PINs are recruited into non‐mobile membrane clusters and their lateral diffusion is dramatically reduced, which ensures longer polar retention. At the circumventing edges of the polar domain, spatially defined internalization of escaped cargos occurs by clathrin‐dependent endocytosis. Computer simulations confirm that the combination of these processes provides a robust mechanism for polarity maintenance in plant cells. Moreover, our study suggests that the regulation of lateral diffusion and spatially defined endocytosis, but not super‐polar exocytosis have primary importance for PIN polarity maintenance. |
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Keywords: | cell polarity membrane trafficking modeling systems biology trafficking Stimulated Emission Depletion microscopy (STED) |
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