TY - JOUR
T1 - Boric acid transport activity of marine teleost aquaporins expressed in Xenopus oocytes
AU - Kumagai, Shiori
AU - Watanabe, Erika
AU - Hayashi, Naoko
AU - Kimura, Yuuri
AU - Kamiya, Takehiro
AU - Nagashima, Ayumi
AU - Ushio, Kazutaka
AU - Imaizumi, Genki
AU - Kim, Juhyun
AU - Munakata, Keijiro
AU - Umezawa, Takahiro
AU - Hirose, Shigehisa
AU - Kasai, Koji
AU - Fujiwara, Toru
AU - Romero, Michael F.
AU - Kato, Akira
N1 - Publisher Copyright:
© 2023 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.
PY - 2023/3
Y1 - 2023/3
N2 - Marine teleosts ingest large amounts of seawater containing various ions, including 0.4 mM boric acid, which can accumulate at toxic levels in the body. However, the molecular mechanisms by which marine teleosts absorb and excrete boric acid are not well understood. Aquaporins (Aqps) are homologous to the nodulin-like intrinsic protein (NIP) family of plant boric acid channels. To investigate the potential roles of Aqps on boric acid transport across the plasma membrane in marine teleosts, we analyzed the function of Aqps of Japanese pufferfish (Takifugu rubripes) expressed in Xenopus laevis oocytes. Takifugu genome database contains 16 genes encoding the aquaporin family members (aqp0a, aqp0b, aqp1aa, aqp1ab, aqp3a, aqp4a, aqp7, aqp8bb, aqp9a, aqp9b, aqp10aa, aqp10bb, aqp11a, aqp11b, aqp12, and aqp14). When T. rubripes Aqps (TrAqps) were expressed in X. laevis oocytes, a swelling assay showed that boric acid permeability was significantly increased in oocytes expressing TrAqp3a, 7, 8bb, 9a, and 9b. The influx of boric acid into these oocytes was also confirmed by elemental quantification. Electrophysiological analysis using a pH microelectrode showed that these TrAqps increase B(OH)3 permeability. These results indicate that TrAqp3a, 7, 8bb, 9a, and 9b act as boric acid transport systems, likely as channels, in marine teleosts.
AB - Marine teleosts ingest large amounts of seawater containing various ions, including 0.4 mM boric acid, which can accumulate at toxic levels in the body. However, the molecular mechanisms by which marine teleosts absorb and excrete boric acid are not well understood. Aquaporins (Aqps) are homologous to the nodulin-like intrinsic protein (NIP) family of plant boric acid channels. To investigate the potential roles of Aqps on boric acid transport across the plasma membrane in marine teleosts, we analyzed the function of Aqps of Japanese pufferfish (Takifugu rubripes) expressed in Xenopus laevis oocytes. Takifugu genome database contains 16 genes encoding the aquaporin family members (aqp0a, aqp0b, aqp1aa, aqp1ab, aqp3a, aqp4a, aqp7, aqp8bb, aqp9a, aqp9b, aqp10aa, aqp10bb, aqp11a, aqp11b, aqp12, and aqp14). When T. rubripes Aqps (TrAqps) were expressed in X. laevis oocytes, a swelling assay showed that boric acid permeability was significantly increased in oocytes expressing TrAqp3a, 7, 8bb, 9a, and 9b. The influx of boric acid into these oocytes was also confirmed by elemental quantification. Electrophysiological analysis using a pH microelectrode showed that these TrAqps increase B(OH)3 permeability. These results indicate that TrAqp3a, 7, 8bb, 9a, and 9b act as boric acid transport systems, likely as channels, in marine teleosts.
KW - aquaglyceroporin
KW - aquaporin
KW - boric acid
KW - electrophysiology
KW - marine teleost
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U2 - 10.14814/phy2.15655
DO - 10.14814/phy2.15655
M3 - Article
C2 - 36967473
AN - SCOPUS:85151044032
SN - 2051-817X
VL - 11
JO - Physiological reports
JF - Physiological reports
IS - 6
M1 - e15655
ER -