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

FEBS Letters

Misaka, Takumi²  Miki, Kazumasa¹  Arai, Soichi²  Abe, Keiko²  Kusakabe, Yuko²  Emori, Yasufumi³  Ichinose, Masao¹  Iwabuchi, Kyoko² 

[1] The First Department of Internal Medicine, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan;Department of Applied Biological Chemistry, Division of Agriculture and Agricultural Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan;Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan

关键词: Aquaporin;    Water channel;    Human stomach;    Gastric parietal cell;    Gastric chief cell;    AQP;    aquaporin;    hAQP4;    human aquaporin 4;    MIWC;    mercurial-insensitive water channel;    nt;    nucleotide(s);    Pf coefficient of osmotic water permeability;    RACE;    rapid amplification of cDNA ends;   

DOI  :  10.1016/0014-5793(96)00092-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown