Overview of mutated human adenosine A2B receptors that were selected based on their ability to produce increased growth in the presence of 4 nM NECA. In addition, the EC50 values of NECA to induce growth via these mutated receptors were determined.
| Mutation | -Fold Constitutive Activity | EC50 Value NECA | -Fold Difference versus wt EC50 |
|---|---|---|---|
| nM | |||
| wt | 1.0 | 97 | 1.0 |
| N36D | 1.4 | 42 | 2.3 |
| N36S V87A | 4.5 | 30 | 3.2 |
| N36S T42A T66Aa | 20 | N.D. | N.D. |
| N36S T42A T66Ab | 22 | N.D. | N.D. |
| T42A | 12 | 20 | 4.9 |
| T42A V54A | 15 | 23 | 4.2 |
| V54La | 11 | 14 | 6.9 |
| V54Lb | 6.9 | 17 | 5.7 |
| F84La | 3.3 | 44 | 2.2 |
| F84Lb | 2.1 | 24 | 4.0 |
| F84S | 7.1 | 15 | 6.5 |
| F84L S95Ga | 6.8 | 5.3 | 18 |
| F84L S95Gb | 8.3 | 5.1 | 19 |
| S91Ga | 1.8 | 56 | 1.7 |
| S91Gb | 3.2 | 66 | 1.5 |
| A18T A23V C83Y A106V R112S | 12 | 35 | 2.8 |
| I242T K269R V284A H302Q | 12 | 9.9 | 9.8 |
| Q214L I230N V240M V250M N254Y T257S K269stop | 18 | — | — |
| Y299C F301C L310P | 6.1 | 21 | 4.6 |
N.D., could not be accurately determined because of the high level of constitutive activity; —, no effect of NECA observed.