FIGURE 3.

GSK3 phosphorylates the MafA S65D and S65E mutants, but not S65A. A, the GSK3 phosphorylation sites in the N-terminal transactivation domain (TAD) and basic leucine zipper (B-Zip) region of MafA are shown (20, 21). B, HeLa cells were transfected with plasmids encoding WT MafA and the Ser⁶⁵ mutant and then treated for 8 h with 50 mm LiCl, as indicated. Nuclear extract was analyzed by Western blotting using anti-MafA antibodies, and a representative blot of this often repeated experiment is presented. Hyper, hyperphosphorylated; Hypo, hypophosphorylated.