Figure 6.

Acute disruption of the deneddylase Jab1 mimics the effects of CUL3-Δ9 expression. (A) Tubule-specific Jab1^−/− mice were made by generating mice with two “floxed” Jab1 alleles and the Pax8-rtTA-LC1 system.²⁰ Mice were treated with doxycycline for 3 weeks to induce recombination to acutely disrupt Jab1, then samples collected 2 weeks later. (B) Western blotting showed that JAB1 expression was significantly reduced, whereas abundance of neddylated Cullins (NEDD8-Cullin) was increased. (C) Jab1^−/− mice displayed higher abundance of neddylated CUL3, and abundances of total (neddylated and unneddylated) CUL3 and KLHL3 were about 50% lower than in controls. (E) Abundances of WNK4 and NCC phosphorylated at T-53 (pNCC-T53) were significantly higher, but total NCC was lower; pNCC-T53/tNCC was significantly higher. Individual values and mean±SEM are shown. Statistical differences were examined by two-tailed unpaired t tests (B and C). *P<0.05; **P<0.01, ***P<0.001.