Affiliation:
1. Laboratoire Reproduction et Développement des Plantes, Université de Lyon
2. University of Tübingen, Center for Plant Molecular Biology (ZMBP)
3. Division of Biological Science, University of Montana
4. Interfaculty Institute for Cell Biology, Department of Quantitative Proteomics, University of Tübingen
5. Faculty of Biology & Biotechnology, Ruhr-University Bochum
Abstract
Membrane lipids, and especially phosphoinositides, are differentially enriched within the eukaryotic endomembrane system. This generates a landmark code by modulating the properties of each membrane. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] specifically accumulates at the plasma membrane in yeast, animal, and plant cells, where it regulates a wide range of cellular processes including endocytic trafficking. However, the functional consequences of mispatterning PI(4,5)P2 in plants are unknown. Here, we functionally characterized the putative phosphoinositide phosphatase SUPPRESSOR OF ACTIN9 (SAC9) in Arabidopsis thaliana (Arabidopsis). We found that SAC9 depletion led to the ectopic localization of PI(4,5)P2 on cortical intracellular compartments, which depends on PI4P and PI(4,5)P2 production at the plasma membrane. SAC9 localizes to a subpopulation of trans-Golgi Network/early endosomes that are enriched in a region close to the cell cortex and that are coated with clathrin. Furthermore, it interacts and colocalizes with Src Homology 3 Domain Protein 2 (SH3P2), a protein involved in endocytic trafficking. In the absence of SAC9, SH3P2 localization is altered and the clathrin-mediated endocytosis rate is reduced. Together, our results highlight the importance of restricting PI(4,5)P2 at the plasma membrane and illustrate that one of the consequences of PI(4,5)P2 misspatterning in plants is to impact the endocytic trafficking.
Funder
Agence Nationale de la Recherche
European Research Council
Deutsche Forschungsgemeinschaft
Publisher
eLife Sciences Publications, Ltd
Subject
General Immunology and Microbiology,General Biochemistry, Genetics and Molecular Biology,General Medicine,General Neuroscience