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DEPC prevents activation of eel Aquaporin 3 by extracellular pH
Author(s) -
Cooper Gordon,
Cramb Gordon,
Walton Kate
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1039.23
Subject(s) - euryhaline , xenopus , urea , extracellular , aquaporin , chemistry , incubation , water transport , histidine , oocyte , biophysics , permeability (electromagnetism) , microbiology and biotechnology , biochemistry , membrane , biology , fishery , embryo , water flow , fish <actinopterygii> , amino acid , environmental engineering , engineering , gene
The European Eel (Anguilla Anguilla), an euryhaline teleost, can survive in a wide range of salinities, and changes in the expression pattern of eAQP3 play a role in the adaptation process. Previously we have shown that when expressed in Xenopus oocytes, eAQP3 increased urea flux, but was not permeable to H 2 O. A recent study suggests that the permeability of eAQP3 to H 2 O is sensitive to pH o . We have investigated the sensitivity of transport by eAQP3 to pH o using the Xenopus oocyte expression system. As expected increasing pH o stimulated P f in oocytes expressing eAQP3. A similar trend was observed for eAQP3‐dependent urea transport with maximum uptake occurring at pH o 8.2. The pH dependent increase in Pf and urea permeability was prevented by a 5min incubation in DEPC. This points to the involvement of an extracellular histidine residue in pH sensing. eAQP3 is expressed in the gill and intestine. Plasma pH lies close to pH8.2 and so transport of water and urea through eAQP3 across the basolateral membrane will be optimal. The transport across the apical membrane will depend on the ambient pH (pH 6.5 – 7.9 for freshwater and pH 7.9 – 8.3 for seawater).