Table 3. Functional characterization of HCA3 orthologs stimulated with aromatic D-amino acids and their metabolites.
CHO-K1 cells were transfected with receptor constructs and cAMP accumulation was determined. The basal cAMP level of mock-transfected CHO-K1 stimulated with 2 μM forskolin (control) in HBSS was 13.8 ± 1.3 nmol/well and set 100%. Emax values are referred to % of mock-transfected CHO-K1 stimulated with 2 μM forskolin in absence of agonist. Emax and EC50 values were determined from concentration-response curves of agonists using GraphPad Prism. A general explanation of EC50 and Emax values is provided in the results section Functional hominoid HCAR analyses with known endogenous agonists. Data is given as mean ± SEM (Emax) and geometric mean with 95% confidence interval (EC50) of at least three independent experiments each performed in triplicates.
| Emax (% of mock-transfected w/o agonist) |
EC50 (μM) (95% CI) |
Emax (% of mock-transfected w/o agonist) |
EC50 (μM) (95% CI) |
Emax (% of mock-transfected w/o agonist) |
EC50 (μM) (95% CI) |
|
|---|---|---|---|---|---|---|
| D-Phe | D-Trp | 3HDec | ||||
| human HCA3 | 21.0 ± 2.3 | 36.1 (17.7–73.5) | 14.7 ± 1.0 | 20.5 (11.7–36.2) | 18.7 ± 2.3 | 31.9 (22.3–45.8) |
| chimpanzee HCA3 | 23.4 ± 2.4 | 37.4 (23.2–60.2) | 22.2 ± 2.2 | 62.1 (47.6–81.0) | 25.7 ± 1.2 | 141(97.5–205) |
| gorilla HCA3 | 17.9 ± 2.3 | 45.7 (27.1–77.1) | 17.8 ±1.5 | 24.4 (23.2–25.8) | 25.8 ± 2.7 | 37.3 (23.0–60.3) |
| orangutan HCA3 | 24.6 ± 2.4 | 129 (103–161) | 24.7 ± 1.5 | 50.7 (30.8–83.4) | 28.4 ± 3.1 | 62.7 (39.8–98.7) |
| siamang HCA3 | 22.9 ± 5.2 | 202 (101–406) | 24.3 ± 1.2 | 56.7 (38.8–82.5) | 35.6 ± 1.0 | 102 (59.9–175) |
| D-PLA | L-PLA | ILA | ||||
| human HCA3 | 20.5 ± 2.8 | 0.15 (0.05–0.42) | 33.4 ± 2.9 | 5.2 (3.0–9.1) | 32.9 ± 2.9 | 0.18 (0.08–0.39) |
| chimpanzee HCA3 | 23.7 ± 1.8 | 0.13 (0.08–0. 22) | 25.4 ± 1.1 | 4.0 (2.4–6.5) | 32.6 ± 4.9 | 0.23 (0.16–0.33) |
| gorilla HCA3 | 19.9 ± 1.4 | 0.085 (0.032–0.21) | 36.5 ±3.0 | 6.2 (4.3–8.9) | 36.3 ±1.7 | 0.073 (0.053–0.10) |
| orangutan HCA3 | 29.3 ± 3.3 | 1.2 (0.60–2.2) | 39.3 ± 3.2 | 6.5 (3.1–13.7) | 42.0± 1.0 | 0.068 (0.030–0.15) |
| siamang HCA3 | 20.4 ± 1.7 | 0.28 (0.14–0.56) | 36.3 ± 3.5 | 17.2 (8.9–33.6) | 33.6 ± 1.2 | 0.17 (0.11–0.28) |