Figure 4.

Inefficient tetramerization of GluA2 L504Y. A, Western blot depicting time course of GluA2L504Y protein expression after induction. B, Coomassie brilliant blue stained 7.5% SDS-PAGE of GluA2 purified from TetOnGluA2L504Y HEK cells. Note only a single band is present. C, Gel filtration chromatograph of GluA2 wild type (red) and L504Y (blue) purified from TetONGluA2 and TetONGluA2L504Y HEK cells, respectively. Proteins were harvested 24 h after induction. Peaks corresponding to tetramer and dimer are indicated. D, Peak fractions from gel filtration in C were resolved and processed for Western blotting using an anti-GluA2 C-terminal antibody. The arrows indicate the glycosylated (upper) and nonglycosylated (lower) bands. Note the absence of any glycosylated GluA2L504Y in the peaks corresponding to tetramers.