Modulation of steady state current responses of iGluRs by tunicamycin or ConA pretreatment
| Receptor Subunit(s) | n1/n2 | Glu | KA | Ratio of ConA potentiation Glu/KA (glycosylated) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Current | ConA potentiation | Current | ConA potentiation | |||||||
| Untreated controls | Tunicamycin-treated | ConA-treated | Tunicamycin- and ConA-treated | Untreated controls | Tunicamycin-treated | ConA-treated | Tunicamycin- and ConA-treated | |||
| nA | % of untreated | fold | fold | nA | % of Untreated | fold | fold | |||
| GluR1flop | 4 /5 | 14 ± 9 | 11 ± 8 | 6.3 ± 4.9 | 2.1 ± 0.9 | 167 ± 43 | 24 ± 12 | 2.4 ± 1.2 | 1.1 ± 0.7 | 2.7 ± 2.4 |
| GluR1flip | 11 /6 | 3.3 ± 1.0 | 198 ± 56 | 12 ± 6 | 1.0 ± 0.2 | 449 ± 139 | 10.3 ± 2.5 | 1.4 ± 0.6 | 1.0 ± 0.3 | 8.6 ± 5.6 |
| GluR2flop | 11 /9 | 0.6 ± 0.2 | 83 ± 43 | 1.2 ± 0.6 | 1.3 ± 0.8 | 1.7 ± 0.5 | 88 ± 33 | 0.9 ± 0.4 | 1.1 ± 0.5 | 1.3 ± 0.9 |
| GluR2flip | 5 /9 | 4.4 ± 1.3 | 227 ± 93 | 1.5 ± 0.7 | 1.5 ± 0.7 | 3.8 ± 1.5 | 106 ± 39 | 0.9 ± 0.5 | 1.4 ± 0.5 | 1.7 ± 1.2 |
| GluR2(Q)flop | 4 /4 | 1164 ± 231 | 68 ± 16 | 1.3 ± 0.5 | 0.7 ± 0.2 | 4498 ± 834 | 54 ± 11 | 1.1 ± 0.3 | 0.9 ± 0.1 | 1.2 ± 0.6 |
| GluR2(Q)flip | 6 /4 | 3319 ± 287 | 172 ± 51 | 1.3 ± 0.3 | 0.9 ± 0.4 | 1751 ± 236 | 95 ± 24 | 0.9 ± 0.2 | 0.7 ± 0.2 | 1.4 ± 0.5 |
| GluR3flop | 5 /5 | 28 ± 17 | 10 ± 7 | 9.3 ± 6.7 | 1.2 ± 0.7 | 92 ± 36 | 23 ± 11 | 1.9 ± 1.1 | 1.1 ± 0.4 | 4.9 ± 4.5 |
| GluR3flip | 4 /5 | 185 ± 41 | 26 ± 11 | 5.7 ± 1.7 | 1.2 ± 0.6 | 1010 ± 262 | 6.4 ± 2.7 | 1.2 ± 0.4 | 1.0 ± 0.4 | 4.8 ± 2.1 |
| GluR4flop | 4 /4 | 1.4 ± 0.4 | 379 ± 143 | 10 ± 4 | 1.1 ± 0.3 | 84 ± 13 | 94 ± 16 | 0.9 ± 0.3 | 0.9 ± 0.1 | 11 ± 6 |
| GluR4flip | 4 /4 | 56 ± 12 | 589 ± 162 | 13 ± 4 | 1.1 ± 0.4 | 361 ± 68 | 69 ± 19 | 1.2 ± 0.4 | 1.0 ± 0.3 | 11 ± 5 |
| GluR1flop/GluR2flop | 4 /4 | 184 ± 53 | 41 ± 13 | 8.6 ± 1.5 | 1.0 ± 0.3 | 1627 ± 215 | 88 ± 13 | 2.2 ± 0.4 | 1.1 ± 0.1 | 3.9 ± 1.0 |
| GluR1flop/GluR2flip | 4 /4 | 369 ± 53 | 30 ± 9 | 8.6 ± 1.5 | 0.8 ± 0.3 | 2389 ± 252 | 29 ± 9 | 2.2 ± 0.3 | 0.9 ± 0.3 | 3.9 ± 0.9 |
| GluR1flip/GluR2flop | 3 /4 | 88 ± 19 | 146 ± 14 | 6.0 ± 1.8 | 1.0 ± 0.5 | 3690 ± 646 | 22 ± 11 | 1.4 ± 0.3 | 1.0 ± 0.5 | 4.3 ± 1.3 |
| GluR1flip/GluR2flip | 4 /4 | 336 ± 28 | 51 ± 11 | 5.1 ± 0.6 | 1.1 ± 0.3 | 4016 ± 260 | 11 ± 2 | 1.4 ± 0.1 | 1.0 ± 0.3 | 3.6 ± 0.5 |
| GluR3flop/GluR2flop | 5 /4 | 166 ± 36 | 87 ± 27 | 8.0 ± 2.4 | 1.1 ± 0.3 | 1808 ± 32 | 39 ± 10 | 1.3 ± 0.3 | 1.2 ± 0.4 | 6.2 ± 2.3 |
| GluR4flop/GluR2flop | 4 /4 | 4.7 ± 1.0 | 143 ± 36 | 3.6 ± 1.2 | 1.1 ± 0.2 | 124 ± 25 | 61 ± 16 | 0.8 ± 0.2 | 1.0 ± 0.2 | 4.5 ± 1.9 |
| GluR5(Q) | 9 /9 | 0 | N.C. | >1544 ± 447 | N.C. | 2.8 ± 1.3 | N.C. | 809 ± 439 | N.C. | 1.9 ± 1.2 |
| GluR6(R) | 3 /7 | 0 | N.C. | >121 ± 37 | N.C. | 0 | N.C. | >133 ± 37 | N.C. | 0.9 ± 0.4 |
| GluR6(Q) | 4 /9 | 2.5 ± 1.0 | 120 ± 77 | 6653 ± 2825 | 0.8 ± 0.4 | 10 ± 2 | 110 ± 37 | 1627 ± 409 | 0.8 ± 0.3 | 4.1 ± 1.7 |
| GluR6(R)/KA1 | 7 /6 | 0 | N.C. | >2.2 ± 0.9 | N.C. | 0 | N.C. | >2.8 ± 1.2 | N.C. | 0.8 ± 0.4 |
| GluR6(Q)/KA1 | 3 /4 | 1.3 ± 0.4 | 646 ± 213 | 2705 ± 1371 | 1.1 ± 0.3 | 3.6 ± 1.2 | 1000 ± 385 | 1053 ± 549 | 0.8 ± 0.2 | 2.6 ± 1.8 |
| GluR6(R)/KA2 | 6 /9 | 2.6 ± 0.4 | N.C. | 19 ± 4 | N.C. | 2.2 ± 0.4 | N.C. | 46 ± 11 | N.C. | 0.4 ± 0.1 |
| GluR6(Q)/KA2 | 5 /4 | 1.0 ± 0.5 | 430 ± 237 | 5984 ± 3345 | 1.1 ± 0.3 | 4.9 ± 1.4 | 200 ± 75 | 1297 ± 493 | 1.0 ± 0.3 | 4.6 ± 3.1 |
| GluR7/KA1/KA2 | 8 /5 | 0 | N.C. | N.C. | N.C. | 0 | N.C. | N.C. | N.C. | N.C. |
| NR1-1a | 5 /5 | 3.5 ± 0.9 | N.C. | 1.5 ± 0.5 | N.C. | |||||
| NR1-1b | 4 /5 | 19 ± 5 | N.C. | 0.5 ± 0.2 | N.C. | |||||
| NR1-2a | /5 | 5.5 ± 0.4 | N.T. | 2.0 ± 0.2 | N.C. | |||||
| NR1-2b | /4 | 34 ± 5 | N.T. | 1.0 ± 0.2 | N.C. | |||||
| NR1-3a | /8 | 16 ± 1 | N.T. | 2.0 ± 0.3 | N.C. | |||||
| NR1-3b | /4 | 50 ± 5 | N.T. | 0.7 ± 0.2 | N.C. | |||||
| NR1-4a | 4 /5 | 4.1 ± 0.5 | N.C. | 2.1 ± 0.6 | N.C. | |||||
| NR1-4b | 4 /4 | 24 ± 2 | N.C. | 0.8 ± 0.1 | N.C. | |||||
| NR1-1a/NR2A | 5 /5 | 392 ± 73 | 0.3 ± 0.1 | 0.3 ± 0.1 | 0.9 ± 0.4 | |||||
| NR1-1a/NR2B | 5 /4 | 1690 ± 138 | 0.4 ± 0.1 | 1.6 ± 0.3 | 0.6 ± 0.1 | |||||
| NR1-1a/NR2C | 5 /4 | 39 ± 2 | N.C. | 0.9 ± 0.1 | N.C. | |||||
| NR1-1a/NR2D | 5 /4 | 62 ± 4 | N.C. | 1.5 ± 0.1 | N.C. | |||||
| NR1-1b/NR2A | 5 /6 | 1254 ± 201 | 1 ± 0.2 | 0.7 ± 0.2 | 0.3 ± 0.1 | |||||
| NR1-1b/NR2B | 6 /4 | 11936 ± 990 | 0.7 ± 0.1 | 0.9 ± 0.1 | 0.9 ± 0.3 | |||||
| NR1-1b/NR2C | 5 /5 | 165 ± 16 | N.C. | 0.6 ± 0.1 | N.C. | |||||
| NR1-1b/NR2D | 4 /5 | 133 ± 12 | N.C. | 0.6 ± 0.1 | N.C. | |||||
| NR1-4a/NR2B | 5 /5 | 3709 ± 666 | 0.2 ± 0.03 | 1.7 ± 0.4 | 0.7 ± 0.3 | |||||
| NR1-4b/NR2B | 4 /5 | 14454 ± 1126 | 0.2 ± 0.03 | 0.7 ± 0.1 | 0.7 ± 0.1 | |||||
AMPA and KA receptors were tested wtih 300 μm Glu or 300 μm KA as agonist, NMDA receptors were activated with 100 μm Glu plus 10 μm glycine. ConA potentiation (in either untreated or tunicamycin-treated cells) was calculated by dividing maximal current responses after an 8-min 10 μm ConA incubation by responses obtained before the ConA treatment. In cases in which no current could be recorded before the ConA treatment, minimal potentiation factors (indicated by >) were calculated by assuming 1 nA of current before treatment. The number of oocytes recorded from is given asn 1/n 2, withn 1 refering to the tunicamycin experiments, andn 2 referring to the ConA experiments. Oocytes were measured 5 or 6 days after cRNA injection. All data represent mean ± standard error. N.C., no currents in treated oocytes; N.T., not tested. The subunit combination GluR7/KA1/KA2 did not give measurable currents under any condition.