Figure 1. Phosphorylation of the intracellular loop1 region of AMPARs by a variety of kinases.

A) Sequence alignment of the intracellular loop1 region of the AMPAR subunits GluA1–4. B) GST, GST-fusion proteins of the loop1 region or the C-terminus of GluA1 were incubated with the indicated kinase and [γ-³²P]-ATP, and analyzed by autoradiography. GelCode blue staining shows the amount of protein used for the assays. A typical result for each condition is shown. The arrowhead in (B) represents a non-specific band. C) As revealed by a phospho-specific immunoblot, purified GST-fusion protein of GluA1 loop1 is in vitro phosphorylated by CK2 and CaMKII on S567. An immunoblot against GST demonstrates that similar amount of protein was used for each condition. The specificity of our phospho-specific antibody against GluA1 pS567 for both CK2 and CaMKII is demonstrated, as GluA1 S567A shows no immunoreactivity.