TY - JOUR
T1 - Boric acid transport activity of human aquaporins expressed in Xenopus oocytes
AU - Ushio, Kazutaka
AU - Watanabe, Erika
AU - Kamiya, Takehiro
AU - Nagashima, Ayumi
AU - Furuta, Tadaomi
AU - Imaizumi, Genki
AU - Fujiwara, Toru
AU - Romero, Michael F.
AU - Kato, Akira
N1 - Funding Information:
This work was supported by JSPS KAKENHI (Grant Number 25650114; 19H05637; and 21K14781), and was partially supported through the Assistant Staffing Program by the Gender Equality Section, Diversity Promotion Office, Tokyo Institute of Technology. The work in the Romero lab was supported by NIH (DK092408; DK100227) and the Mayo Foundation.
Publisher Copyright:
© 2022 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.
PY - 2022/1
Y1 - 2022/1
N2 - Boric acid is a vital micronutrient that is toxic at high concentrations in animals. However, the mechanisms underlying boric acid transport in animal cells remain unclear. To identify the plasma membrane boric acid channels in animals, we analyzed the function of human aquaporins (AQPs), which are homologous to the nodulin-like intrinsic protein family of plant boric acid channels. When human AQPs were expressed in Xenopus laevis oocytes, the results of the swelling assay showed that boric acid permeability significantly increased in oocytes expressing AQP3, 7, 8, 9, and 10, but not in those expressing AQP1, 2, 4, and 5. The boric acid influxes of these oocytes were also confirmed by elemental quantification. Electrophysiological analysis using a pH microelectrode showed that these AQPs transported boric acid (B(OH)3) but not borate ions (B(OH)4–). These results indicate that AQP3, 7, 8, 9, and 10 act as boric acid transport systems, likely as channels in humans.
AB - Boric acid is a vital micronutrient that is toxic at high concentrations in animals. However, the mechanisms underlying boric acid transport in animal cells remain unclear. To identify the plasma membrane boric acid channels in animals, we analyzed the function of human aquaporins (AQPs), which are homologous to the nodulin-like intrinsic protein family of plant boric acid channels. When human AQPs were expressed in Xenopus laevis oocytes, the results of the swelling assay showed that boric acid permeability significantly increased in oocytes expressing AQP3, 7, 8, 9, and 10, but not in those expressing AQP1, 2, 4, and 5. The boric acid influxes of these oocytes were also confirmed by elemental quantification. Electrophysiological analysis using a pH microelectrode showed that these AQPs transported boric acid (B(OH)3) but not borate ions (B(OH)4–). These results indicate that AQP3, 7, 8, 9, and 10 act as boric acid transport systems, likely as channels in humans.
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U2 - 10.14814/phy2.15164
DO - 10.14814/phy2.15164
M3 - Article
C2 - 35014212
AN - SCOPUS:85123459398
SN - 2051-817X
VL - 10
JO - Physiological Reports
JF - Physiological Reports
IS - 1
M1 - e15164
ER -