Table 1.
Effect of CaMKII and GluA1-Ser831 phosphomimic and phosphodeficient mutations on weighted mean unitary conductance (γMEAN) of homomeric and heteromeric GluA1-containing receptors expressed in HEK cells. Some cells were co-transfected with a cDNA encoding the PKI inhibitor peptide9
| Mutation | TARPs | Method | γMEAN | PO | N | |
|---|---|---|---|---|---|---|
| GluA1/PKI | WT | -- | Non-stationary | 12.0 ± 1.0 | 0.53 ± 0.08 | 9 |
| GluA1/PKI + CaMKII | WT | -- | Non-stationary | 20.4 ± 2.9 * | 0.74 ± 0.03 * | 11 |
| GluA1/PKI | S831A | -- | Non-stationary | 12.9 ± 1.2 | 0.35 ± 0.06 | 8 |
| GluA1/PKI + CaMKII | S831A | -- | Non-stationary | 11.1 ± 1.7 | 0.36 ± 0.05 | 10 |
| GluA1 | L497Y | -- | Stationary | 12.4 ± 0.3 | 0.77 ± 0.02 | 19 |
| GluA1 + CaMKII | L497Y | -- | Stationary | 17.6 ± 0.4 * | 0.76 ± 0.02 | 22 |
| GluA1 | L497Y, S831A, S845A | -- | Stationary | 9.4 ± 0.7 | 0.79 ± 0.03 | 18 |
| GluA1 | L497Y, S831E, S845A | -- | Stationary | 14.2 ± 0.6 ** | 0.73 ± 0.03 | 19 |
| GluA1 | L497Y, S831D, S845D | -- | Stationary | 13.1 ± 1.0 ** | 0.75 ± 0.02 | 12 |
| GluA1 | L497Y, S831A, S845A | Stargazin | Stationary | 12.3 ± 1.1 | 0.96 ± 0.03 ** | 13 |
| GluA1 | L497Y, S831E, S845A | Stargazin | Stationary | 16.9 ± 1.0 ** | 0.95 ± 0.02 ** | 8 |
| GluA1/GluA2 | L497Y, S831A, S845A | -- | Stationary | 2.6 ± 0.5 | 0.78 ± 0.03 | 8 |
| GluA1/GluA2 | L497Y, S831E, S845A | -- | Stationary | 3.0 ± 0.2 | 0.82 ± 0.02 | 11 |
| GluA1/GluA2 | L497Y, S831A, S845A | Stargazin | Stationary | 3.8 ± 0.4 | 0.71 ± 0.02 | 10 |
| GluA1/GluA2 | L497Y, S831E, S845A | Stargazin | Stationary | 6.2 ± 0.9 *** | 0.79 ± 0.05 | 12 |
| GluA1/GluA2 | L497Y, S831A, S845A | γ8 | Stationary | 3.0 ± 0.4 | 0.68 ± 0.07 | 10 |
| GluA1/GluA2 | L497Y, S831E, S845A | γ8 | Stationary | 6.4 ± 1.4 *** | 0.78 ± 0.07 | 11 |
Weighted mean unitary conductance, γMEAN, was determined using either non-stationary or stationary variance analysis of current responses obtained from transfected HEK cells. Values are mean ± SEM; N is the number of outside-out patches studied at a holding potential of −60 mV.
p < 0.05 significantly different from control (recordings lacking CaMKII); there was no significant difference between GluA1-S831A, GluA1-S831A + CaMKII or WT GluA1 control (ANOVA).
p < 0.01 significantly different from GluA1-L497Y,S831A,S845A, GluA1-L497Y,S831E,S845A or from GluA1-L497Y,S831A,S845A + stargazin (One-way ANOVA, with Tukey’s post hoc test). Coexpression with stargazin is described in the Methods.
p < 0.05 significantly different from heteromeric receptors containing GluA1-L497Y,S831A,S845A mutant subunits (One-way ANOVA, with Tukey’s post hoc test). Open probability (PO) was calculated as the ratio of the maximal macroscopic current to the product of the fitted unitary current and number of channels. One-way ANOVA was used to compare PO values for homomeric GluA1 L497Y mutant and GluA1/GluA2 receptor responses.