Fig 4.
AqpZ is insensitive to inhibition by mercury in Xenopus oocytes and in Synechocystis. (A) Effects of mercury, the protein kinase C activator PMA, and pH on water permeability in Xenopus oocytes expressing AqpZ. HgCl2 (300 μM) or PMA (10 μM) was added to the incubation medium 5 min before the start of the swelling assay. The mercury-sensitive human aquaporin hAQP1 was used as a control. (B) Test of inhibition of water permeability by HgCl2. Synechocystis WT and ΔaqpZ cells were pretreated with BG11 medium containing 300 μM HgCl2 for 5 min before subjecting them to hyperosmotic shock (BG11 medium containing 0.5 M sorbitol). Values are expressed as the mean Pf ± SD calculated for three independent experiments.