Figure 7.
Role of Ser38 and His39-His40 on Atlantic salmon Aqp0a1 and -0b2 pH sensitivity. Osmotic water permeability (Pf) of X. laevis oocytes injected with water or cRNA encoding wild-type Aqp0a1 or Aqp0b2 or different mutants in which Ser39 was replaced by Pro in Aqp0a1 (Aqp0a1-S39P) or in which a single His in position 39 or 40 replaced the double His in Aqp0b2 (Aqp0b2–H40N and Aqp0b2-H39N, respectively). The Pf was calculated using an estimated surface area of 9× the geometric area. Oocytes were exposed to different pH before and during the swelling assays. Data are the mean ± sem (n = 12 oocytes per construct) of a representative experiment. Significant differences (*P < 0.05; **P < 0.01; ***P < 0.001) for each construct at the 3 pHs are indicated. The bracket indicates significant differences with respect water-injected oocytes. NS, not significant.