Comparison of the deduced amino acid sequence of Japanese eel AQP1b with those of European eel, Senegal sole, gilthead seabream and zebrafish. The six transmembrane (TM) domains and connecting loops (A-E) are indicated by brackets and horizontal arrows, respectively. Two Asn-Pro-Ala (NPA) motifs are emboldened. The antibody was raised against a synthetic peptide corresponding to the underlined sequence. The numbers on the right correspond to amino acid positions in the protein sequences.