FIG. 4.
Detection of Rex-2 phosphorylation mutants in 293 T cells. Transfection, immunoprecipitation, and SDS-PAGE analysis were performed as described in the legend to Fig. 2. Wild-type (Wt) Rex, various Rex mutants, and the control are indicated. The data indicate that serines 151 and 153 are required for the phosphorylation-induced mobility shift from p24rex to p26rex and that replacement of either one or both serines 151 and 153 with aspartic acid locks the protein in a phosphorylated conformation. Lane M, markers.