Figure 6.

Mutation of PKC phosphorylation sites in the C-terminal domain of GluR5-2b abolishes receptor rundown. (A) Amino-acid sequence of the C-terminal domain of GluR5-2b. Serine targets for PKC phosphorylation are shown in bold. Underlined residues correspond to the ER retention signal identified, and the boxed region is the PDZ binding domain. (B) Examples of KA-induced responses in GluR5-2b double mutants expressed in SHSY5-Y cells before and after a 3 min exposure to PdBu. (C) PdBu-induced rundown of mutated GluR5-2b was minimal (n=10 cells). For comparison, the rundown obtained from wild-type construct (as in Figure 4B) is also shown in this graph.