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GNOM‐dependent endocytosis maintains polar localisation of the borate exporter BOR1 in Arabidopsis
Author(s) -
Yoshinari Akira,
Toda Yosuke,
Takano Junpei
Publication year - 2021
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1111/boc.202000106
Subject(s) - endocytosis , biology , microbiology and biotechnology , brefeldin a , endocytic cycle , endosome , guanine nucleotide exchange factor , vacuole , transport protein , dynamin , gtpase , cytoplasm , biochemistry , receptor , golgi apparatus , endoplasmic reticulum , intracellular
Background Information Plants use transporters polarly localised in the plasma membrane for the directional transport of nutrients. The boric acid/borate (B) exporter BOR1 is localised polarly in the inner lateral domain of the plasma membrane in various root cells for efficient translocation of B under B limitation. With a high B supply, BOR1 is ubiquitinated and transported to vacuoles for degradation. The polar localisation and vacuolar targeting of BOR1 are maintained by different endocytosis mechanisms. Results We demonstrated that one of the most utilised inhibitors in endosomal recycling, brefeldin A (BFA), inhibits the polar localisation of BOR1. BFA inhibits a subset of guanine‐nucleotide exchange factors (ARF‐GEFs), regulators of vesicle formation. Using a transgenic line expressing BFA‐resistant engineered GNOM, we identified GNOM as the key ARF‐GEF in endocytosis and maintenance of the polar localisation of BOR1. Conclusions and Significance We found that BFA inhibits the polar localisation of BOR1 by inhibiting GNOM activity. Our results suggest that GNOM‐dependent endocytosis contributes to the maintenance of the polar localisation of BOR1 under B limitation. We propose a model of BOR1 transcytosis initiated from GNOM‐dependent endocytosis.