Effects of short-term agonist exposure on the desensitization of A3AR function in CHO cells stably expressing WT and Thr307,318,319 → Ala-mutated A3ARs
| WT A3AR | Thr307,318,319 → Ala | |||
|---|---|---|---|---|
| Control | Treated | Control | Treated | |
| Basal activity (pmol/min/mg) | 2.8 ± 0.5 | 3.3 ± 0.4 | 3.8 ± 1.1 | 3.0 ± 0.6 |
| F.S. at 5 μM forskolin | 9.4 ± 1.1 | 10.8 ± 0.6 | 13.3 ± 4.8 | 10.3 ± 0.7 |
| IC50 (nM) | 62 ± 30 | 347 ± 552-150 | 176 ± 38 | 396 ± 602-150 |
| Fold increase in IC50 | 5.60 | 2.25 | ||
| Maximal inhibition (%) | 72 ± 9 | 58 ± 8 | 51 ± 6 | 57 ± 2 |
CHO cells stably expressing either the WT A3AR or a mutant A3AR in which Thr307, Thr318, and Thr319 were converted to Ala (Thr307,318,319 → Ala) were treated for 10 min at 37°C with or without 5 μM (R)-PIA before membrane preparation and assay of IBMECA-mediated inhibition of 5 μM forskolin-stimulated adenylyl cyclase activity and analysis as described in Experimental Procedures. Data are presented from three experiments.
↵2-150 Statistically significant difference (P < .05) from untreated controls.
F.S., fold stimulation over basal activity.