Substitutions (c.196AGC>GAG) were engineered in codon 196 in exon 6, changing it from a serine to a glutamate codon (p.Ser196Glu or p.S196E). A loxP site flanked neomycin resistance gene was inserted into intron 7. the neo cassette was removed through subsequent cre-mediated recombination. In the peptide the mutation acts as a phosphomimetic. (J:242315)