Table 2.
EC50, fold of EC50, and E max values of wild-type and mutant A2B receptors in all examined MMY strains. The fold shift of EC50 was calculated by dividing the EC50 of the mutant receptor by the EC50 of the wild-type receptor of the same strain. %E max represents the intrinsic activity of the receptor, where the mean maximal growth level of MMY12 carrying wild-type receptor in response to the agonist NECA (10−4 M) was set as 100 %. Results were mostly obtained from two independent experiments, performed in duplicate (individual values in parentheses)
| EC50 | Fold EC50 | % E max | ||
|---|---|---|---|---|
| MMY 12 (GαWT) | Wild type | 393 ± 92 | 1 | 100 ± 3 |
| R1033.50A | – | – | 13 (17, 9) | |
| I1073.54A | – | – | 0 (0, 1) | |
| L213IL3A | 236 (152, 319) | 0.6 | 100 (104, 96) | |
| S2356.36A | 384 (309, 459) | 1 | 85 (83, 87) | |
| L2366.37A | 3,099 (2,503, 3,694) | 7.9 | 102 (109, 96) | |
| MMY 14 (Gαq) | Wild type | 1,641 ± 552 | 1 | 99 ± 3 |
| R1033.50A | – | – | 1 (1, 1) | |
| I1073.54A | – | – | (0, 0) | |
| L213IL3A | 483 (461, 504) | 0.3 | 76 (75, 77) | |
| S2356.36A | 3,109 (2,102, 4,115) | 1.9 | 50 (48, 51) | |
| L2366.37A | 7,069 (9,827, 4,310) | 4.3 | 83 (83, 82) | |
| MMY 19 (Gα12) | Wild type | 2,843 ± 1,141 | 1 | 91 ± 8 |
| R1033.50A | – | – | 2 (2, 1) | |
| I1073.54A | – | – | 1 (0, 1) | |
| L213IL3A | 272 (199, 345) | 0.1 | 100 (100, 99) | |
| S2356.36A | – | – | 19 (8, 31) | |
| L2366.37A | – | – | 50 (60, 40) | |
| MMY 20 (Gα13) | Wild type | 384 ± 158 | 1 | 99 ± 7 |
| R1033.50A | – | – | 6 (10, 2) | |
| I1073.54A | – | – | 3 (3, 3) | |
| L213IL3A | 90 (42, 137) | 0.2 | 102 (107, 97) | |
| S2356.36A | 437 (501, 372) | 1.1 | 77 (75, 80) | |
| L2366.37A | 5,375 (4,700, 6,050) | 14 | 85 (87, 84) | |
| MMY 21 (Gα14) | Wild type | 212 ± 91 | 1 | 108 ± 7 |
| R1033.50A | – | – | 4 (5, 2) | |
| I1073.54A | – | – | 1 (0, 1) | |
| L213IL3A | 34 (17, 51) | 0.2 | 107 (108, 106) | |
| S2356.36A | 664 (552, 776) | 3.1 | 80 (78, 82) | |
| L2366.37A | 1,335 (783, 1,887) | 6.3 | 99 (104, 94) | |
| MMY 23 (Gαi1) | Wild type | 305 ± 137 | 1 | 91 ± 8 |
| R1033.50A | – | – | 9 (15, 3) | |
| I1073.54A | 7,629 (9,162, 6,095) | 25 | 37 (38, 37) | |
| L213IL3A | 108 (72, 143) | 0.4 | 95 (96, 94) | |
| S2356.36A | 84 (103, 65) | 0.3 | 82 (76, 88) | |
| L2366.37A | 411 (398, 424) | 1.3 | 98 (102, 95) | |
| MMY 24 (Gαi3) | Wild type | 59 ± 10 | 1 | 113 ± 5 |
| R1033.50A | – | – | 9 (7, 10) | |
| I1073.54A | – | – | 2 (2, 1) | |
| L213IL3A | 49 (25, 72) | 0.8 | 104 (113, 96) | |
| S2356.36A | 175 (174, 176) | 3 | 105 (109, 102) | |
| L2366.37A | 680 (504, 855) | 11.6 | 112 (121, 103) | |
| MMY 28 (Gαs) | Wild type | 25 ± 6 | 1 | 112 ± 4 |
| R1033.50A | 57 (53, 61) | 2.2 | 95 (98, 92) | |
| I1073.54A | 47 (25, 69) | 1.9 | 103 (100, 106) | |
| L213IL3A | 23 (31, 15) | 0.9 | 105 (104, 106) | |
| S2356.36A | 33 (42, 24) | 1.3 | 105 (110, 100) | |
| L2366.37A | 538 (755, 321) | 21 | 96 (95, 98) |