A water channel closely related to rat brain aquaporin 4 is expressed in acid‐ and pepsinogen‐secretory cells of human stomach

FEBS Letters - Tập 381 - Trang 208-212 - 1996
Takumi Misaka1, Keiko Abe1, Kyoko Iwabuchi1, Yuko Kusakabe1, Masao Ichinose2, Kazumasa Miki2, Yasufumi Emori3, Soichi Arai1
1Department of Applied Biological Chemistry, Division of Agriculture and Agricultural Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
2The First Department of Internal Medicine, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
3Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

Tóm tắt

We isolated a cDNA clone encoding a water channel protein, aquaporin (AQP), from human stomach. The encoded protein consisted of 323 amino acid residues, containing six putative transmembrane domains. The protein was designated human aquaporin 4 (hAQP4) because of its 94% sequence similarity to rat brain AQP4. Expression of hAQP4 cRNA in Xenopus oocytes resulted in a significant increase in osmotic water permeability, indicating that this protein functions as a water channel. Northern blot analysis demonstrated a strong signal of hAQP4 mRNA in brain, lung, and skeletal muscle as well as in stomach. Immunohistochemical experiments with human stomach tissues showed that hAQP4 as a protein is expressed mainly in cells located in the glandular portion of the fundic mucosa. These include chief cells which secrete pepsinogen and parietal cells which secrete hydrochloric acid. These results strongly indicate that hAQP4 is a principal factor involved in the osmotic regulation of pepsinogen and acid secretion in the stomach.

Tài liệu tham khảo

10.1152/ajprenal.1993.265.3.F461 Knepper M.A., 1994, Proc. Natl. Acad. Sci. USA, 6255 10.1016/0968-0004(94)90091-4 10.1016/0955-0674(95)80003-4 10.1016/S0021-9258(19)37635-5 10.1016/S0021-9258(18)38133-X Preston G.M., 1991, Proc. Natl. Acad. Sci. USA, 11110 10.1038/361549a0 Ishibashi K., 1994, Proc. Natl. Acad. Sci. USA, 6269 Echevarria M., 1994, Proc. Natl. Acad. Sci. USA, 10997 Jung J.S., 1994, Proc. Natl. Acad. Sci. USA, 13052 10.1074/jbc.270.4.1908 10.1152/ajpcell.1992.263.6.C1225 10.1083/jcb.120.2.371 10.1152/ajpcell.1993.264.1.C237 Bondy C., 1993, Proc. Natl. Acad. Sci. USA, 4500 Folkesson H.G., 1994, Proc. Natl. Acad. Sci. USA, 4970 Nielsen S., 1993, Proc. Natl. Acad. Sci. USA, 11663 Fushimi K., 1994, Am. J. Physiol., 267, F573 10.1152/ajpcell.1994.266.4.C893 Nielsen S., 1993, Proc. Natl. Acad. Sci. USA, 7275 Van Os C.H., 1994, Biochim. Biophys. Acta, 291 Frohman M.A., 1988, Proc. Natl. Acad. Sci. USA, 8998 10.1126/science.256.5055.385 10.1016/S0021-9258(17)37486-0
Thông tin
Thông tin xuất bản

FEBS Letters

Tập 381

208-212

Thông tin tác giả