Polar localization and degradation of Arabidopsis boron transporters through distinct trafficking pathways
- 16 March 2010
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (11), 5220-5225
- https://doi.org/10.1073/pnas.0910744107
Abstract
Boron (B) is essential for plant growth but is toxic when present in excess. In the roots of Arabidopsis thaliana under B limitation, a boric acid channel, NIP5;1, and a boric acid/borate exporter, BOR1, are required for efficient B uptake and subsequent translocation into the xylem, respectively. However, under high-B conditions, BOR1 activity is repressed through endocytic degradation, presumably to avoid B toxicity. In this study, we investigated the localization of GFP-tagged NIP5;1 and BOR1 expressed under the control of their native promoters. Under B limitation, GFP-NIP5;1 and BOR1-GFP localized preferentially in outer (distal) and inner (proximal) plasma membrane domains, respectively, of various root cells. The polar localization of the boric acid channel and boric acid/borate exporter indicates the radial transport route of B toward the stele. Furthermore, mutational analysis revealed a requirement of tyrosine residues, in a probable cytoplasmic loop region of BOR1, for polar localization in various cells of the meristem and elongation zone. The same tyrosine residues were also required for vacuolar targeting upon high B supply. The present study of BOR1 and NIP5;1 demonstrates the importance of selective endocytic trafficking in polar localization and degradation of plant nutrient transporters for radial transport and homeostasis of plant mineral nutrients.Keywords
This publication has 38 references indexed in Scilit:
- A developmental framework for endodermal differentiation and polarityProceedings of the National Academy of Sciences of the United States of America, 2010
- Differential degradation of PIN2 auxin efflux carrier by retromer-dependent vacuolar targetingProceedings of the National Academy of Sciences of the United States of America, 2008
- Coordinated protein sorting, targeting and distribution in polarized cellsNature Reviews Molecular Cell Biology, 2008
- Generation of cell polarity in plants links endocytosis, auxin distribution and cell fate decisionsNature, 2008
- The Endosomal System of Plants: Charting New and Familiar TerritoriesPlant Physiology, 2008
- Endosomal signaling of plant steroid receptor kinase BRI1Genes & Development, 2007
- Targeting of the Plant Vacuolar Sorting Receptor BP80 Is Dependent on Multiple Sorting Signals in the Cytosolic TailPlant Cell, 2006
- The Arabidopsis Major Intrinsic Protein NIP5;1 Is Essential for Efficient Boron Uptake and Plant Development under Boron LimitationPlant Cell, 2006
- Slow Diffusion of Proteins in the Yeast Plasma Membrane Allows Polarity to Be Maintained by Endocytic CyclingCurrent Biology, 2003
- Signals for Sorting of Transmembrane Proteins to Endosomes and LysosomesAnnual Review of Biochemistry, 2003