Table 2.
Functional Characterization of PTHR1 and PTHR1 Mutants
| Construct | PTH-Stimulated Adenylyl Cyclase Activity
|
|
|---|---|---|
| EC50 (nm) | ECmax (Fold Increase over Basal) | |
| PTHR1 (wt) | 3.5 ± 1.0 | 31.7 ± 9.2 |
| XM-PTHR1 (XM) | 1.7 ± 0.5 | 35.4 ± 2.6 |
| F238C/F447C (FF) | 3.0 ± 3.8 | 14.6 ± 4.7 |
| V239C/F447C (VF) | No activity | No activity |
| K240C/F447C (KF) | 1.7 ± 0.3 | 12.0 ± 2.7 |
| D241C/F447C (DF) | 2.6 ± 1.4 | 7.4 ± 5.2 |
| A242C/F447C (AF) | 9.6 ± 5.8 | 15.8 ± 12.3 |
PTH-stimulated adenylyl cyclase activity assays were carried out in Cos-7 cells transfected with wtPTHR1 or mutant PTHR1 constructs. PTH was used as agonist (see Materials and Methods). EC50 values were calculated by nonlinear regression analysis of concentration curves using GraphPad Prism software. The data are expressed as mean ± se of three separate experiments, each performed in triplicate. ECmax values are expressed as fold increase in activity observed with 1 μm PTH over basal activity.