Mutations were engineered in exon 27 to change serine codons (TCA) 1160 and 1180 to alanine codons (CGA) (p.S1160A, p.S1180A). The loxP site flanked neomycin resistance gene cassette that was inserted into intron 27 was removed through subsequent cre-mediated recombination. The substitution of the two serines with alanines prevents the phosphorylation of these two residues. (J:198425)