Table 1.
Summary of the endogenous melanocortin agonist and Ac-His-DPhe-Arg-Trp-NH2 (JRH887-9) ligand pharmacology at the hMC4R polymorphisms.
| Mutation | TM | α-MSH EC50 (nM) | β-MSH EC50 (nM) | γ2-MSH EC50 (nM) | ACTH(1-24) EC50 (nM) | JRH887-9 EC50 (nM) |
|---|---|---|---|---|---|---|
| WT# | 1.34±0.5 | 0.30±0.05 | 107±32 | 1.63±0.3 | 0.57±0.05 | |
| R7H | N-Term | 0.82±0.23 | 0.18±0.04 | 77.2±26 | 3.77±2.5 | 0.63±0.13 |
| R18H | N-Term | 1.34±0.7 | 0.10±0.01 | 79.3±19 | 2.06±0.7 | 0.43±0.07 |
| R18L | N-Term | 0.87±0.6 | 0.21±0.05 | 100±54 | 2.25±0.8 | 0.47±0.08 |
| S36Y | N-Term | 0.88±0.3 | 0.51±0.19 | 196±74 | 6.86±3.3 | 0.86±0.19 |
| P48S | 1 | 3.27±1.4* | 0.74±0.16 | 150±11 | 4.50±1.3 | 3.60±0.26* |
| V50M | 1 | 1.72±0.5 | 0.54±0.09 | 128±33 | 4.38±0.1 | 0.68±0.08 |
| F51L | 1 | 17.1±4.3* | 7.71±1.7* | 1134±260* | 107±24* | 37.3±11.3* |
| E61K | 1 | 82±53* partial agonist | 43.7±15* partial agonist | 1450±860* partial agonist | 188±66* partial agonist | 149±25* partial agonist |
| I69T | 1 | 13.6±1.1* | 9.52±3.1* | 278±5.7* | 32.6±3.8* | 40.7±5.1* |
| D90N | 2 | 226±77* partial agonist | 66±36* partial agonist | 6875±1070* partial agonist | 240±26* partial agonist | 746±250* partial agonist |
| S94R | 2 | No stim | No stim | No stim | No stim | No stim |
| G98R | 2 | No stim | No stim | No stim | No stim | No stim |
| I102T/V103I | 2 | 19.2±2.9* | 3.90±1.5* | 548±153* | 42.6±7.5* | 16.1±3.6* |
| I121T | 3 | 1.06±0.48 | 0.95±0.30 | 256±112 | 7.42±1.6 | 4.32±0.35* |
| A154D | IL2 | 5.25±2.4* | 0.67±0.01 | 427±55* | 14.0±2.2* | 4.37±0.6* |
| Y157S | IL2 | 265±66* partial agonist | 168±42* partial agonist | 2540±170* partial agonist | 177±49* partial agonist | 1185±150* partial agonist |
| W174C | 4 | No stim | No stim | No stim | No stim | No stim |
| G181D | 4 | No stim | No stim | No stim | No stim | No stim |
| F202L | 5 | 0.74±0.68 | 0.85±0.78 | 240±180 | 3.74±1.64 | 1.59±0.84 |
| A219V | 5 | 15.4±1.13* | 4.36±0.37* | 594±65* | 79.3±4.95* | 9.78±1.12* |
| I226T | IL3 | 1.30±0.96 | 0.53±0.11 | 110±35 | 7.53±3.04 | 0.84±0.17 |
| G231S | IL3 | 1.62±1.32 | 0.41±0.11 | 164±73 | 3.11±0.49 | 1.88±0.28* |
| G238D | IL3/6 | 2.15±0.63 | 0.19±0.01 | 92.7±13.3 | 3.62±1.16 | 0.65±0.09 |
| N240S | IL3/6 | 1.06±0.71 | 0.35±0.11 | 189±108 | 1.39±0.47 | 0.76±0.06 |
| 750DELGA | 6 | No stim | No stim | No stim | No stim | No stim |
| C271R | 6/EX3 | 350±80.5* partial agonist | 342±131* partial agonist | 6480±1130* partial agonist | 487±85* partial agonist | 1600±1060* partial agonist |
| S295P | 7 | 1.10±0.21 | 0.69±0.009 | 160±130 | 5.96±2.5 | 2.77±0.12* |
| P299L | 7 | No stim | No stim | No stim | No stim | No stim |
| E308K | C-Term | 2.96±0.72 | 0.81±0.11 | 116±31 | 6.03±2.59 | 0.96±0.29 |
| I317V | C-Term | 1.42±0.45 | 0.60±0.24 | 140±47 | 4.78±2.14 | 1.42±0.28 |
| L325F | C-Term | 0.35±0.04 | 0.33±0.08 | 90±47 | 3.47±1.67 | 0.98±0.40 |
Indicates the average from seven independent experiments of HEK-293 cells stably expressing the wild type (WT) hMC4R. These WT values represent those obtained while running parallel experiments with the receptors reported in this study. The values indicated represent the mean of at least three independent experiments with the standard error of the mean indicated. No stim indicates that the endogenous agonists were unable to stimulate the receptor polymorphisms at up to 1 μM concentrations. Partial agonist indicates that some stimulatory agonist pharmacology resulted, but the maximal stimulation levels were less then the wild type control response. Statistical analysis was performed using a student T-test compared to the wild type receptor values with
p<0.05.